If x+y=15 and x-y=25, then what is the value of 2x^2 - y^2?

Answers

Answer 1

Answer:

775

Step-by-step explanation:

We are given two equations in which we can perform systems of equations by putting these two equations on top of each other then solving for one variable:

x+y=15

x-y=25

Here, we can cancel out the y variable and get:

2x=40

x=20

Then we can put the x variable into any of the equations to solve for y (in this case I will use the equation x+y=15 so 20+y=15

y=-5

Now, we can solve by plugging both variables into 2x^2 - y^2 :

2(20)^2 - (-5)^2

800-25 = 775

I hope this helps!

Answer 2

Answer:

775

Step-by-step explanation:

Hi there!

We are given the following system of equations:

x+y=15

x-y=25

and we need to find the value of 2x²-y²

First, let's find the value of x and y

Let's add the 2 equations together to clear y and solve for x (y-y=0)

2x=40

divide both sides by 2

x=20

Now substitute 20 as x into either one of the equations to solve for y

To do x-y=25 for instance,

20-y=25

subtract 20 from both sides

-y=5

multiply both sides by -1

y=-5

Now we know that x=20 and y=-5

Substitute those values into the expression (remember: y² is equal to y×y, or (y)²)

2(20)²-(-5)²

Raise to the second power

2(400)-(25)

multiply and open parenthesis

800-25

subtract

775

Hope this helps!


Related Questions

What is the answer for this equation

Answers

Answer:

the answer is -5,-7,-10,-14,-19

How do I complete the table?​

Answers

Answer:

From left to right, fill in 3.5 and 6.5

Step-by-step explanation:

Use the given formula to calculate y for the given values of x.

When x = 0.5, y = 3(0.5) + 1/0.5

y = 1.5 + 2

y = 3.5 if x = 0.5

When x = 2, y = 3(2) + 1/2

y = 6 + 0.5

y = 6.5 if x = 2

solve |x + 5| = -7 ....

Answers

Answer:

2,-12

Step-by-step explanation:

The given equation is ,

[tex]\implies |x + 5 | = -7 [/tex]

We know that modulus only gives positive value , Therefore on squaring both sides we have ,

[tex]\implies (x + 5 )^2=( -7)^2 \\\\\implies (x+5)^2=7^2\\\\\implies x + 5 =\pm 7 \\\\\implies x = 7-5,-7-5 \\\\\implies \boxed{ x = 2, -12} [/tex]

Which is expression is equivalent to (x^-4y/x^-9y^5)^-2

Answers

Answer:

[tex]\frac{y^8}{x^{10}}[/tex]

Step-by-step explanation:

Given

[tex](\frac{x^{-4}y}{x^{-9}y^5})^{-2}[/tex]

Required

The equivalent

Apply law of indices to the inner bracket

[tex](x^{-4--9}y^{1 -5})^{-2}[/tex]

[tex](x^{5}y^{-4})^{-2}[/tex]

Rewrite as:

[tex]\frac{1}{(x^{5}y^{-4})^2}[/tex]

Expand

[tex]\frac{1}{(x^{5*2}y^{-4*2})}[/tex]

[tex]\frac{1}{(x^{10}y^{-8})}[/tex]

Apply law of indices

[tex]\frac{y^8}{x^{10}}[/tex]

x^4+64 will be the perfect square by adding

Answers

Answer:

[tex]( { {x}^{2} })^{2} + 16 {x}^{2} + {8}^{2} \\ ( {x}^{2} + 8) ^{2} \\ ( { {x}^{2} })^{2} - 16 {x}^{2} + {8}^{2} \\ ( {x}^{2} - 8) ^{2} [/tex]

+16x² or -16x² is the answer

solve for y
[tex]2y - 3 = \sqrt{ {3y}^{2} - 10y + 12} [/tex]
absurd answers will be reported!!​

Answers

Answer:

y = 3

Step-by-step explanation:

2y - 3 = [tex]\sqrt{3y^2-10y+12}[/tex]

square both sides to remove sqrt bracket

(2y - 3)^2 = ( [tex]\sqrt{3y^2-10y+12}[/tex] )^2

simplify both sides

(2y - 3)(2y - 3) = [tex]3y^2[/tex] - 10y + 12

[tex]4y^2[/tex] - 12y + 9 = [tex]3y^2[/tex] - 10y + 12

bring all value to left side

[tex]y^2[/tex] - 2y - 3 = 0

factor

(y - 3)(y + 1)

solve for y

y = 3, y = -1

When plugged back into the equation, only y = 3 is true

Answer:

y = 3

Step-by-step explanation :

[tex]2y - 3 = \sqrt{ 3y² - 10y + 12} [/tex]

Swap the sides both of the equation.

[tex]\sqrt{ 3y² - 10y + 12} = 2y - 3 [/tex]

To remove the brackets of equations square both side and simplify .

3y² - 10y + 12 = 4y² - 12y + 9

Move the expression to left-hand side and change its sign.

3y² - 10y + 12 - 4y² + 12y - 9 = 0

collect like terms

3y² - 4y² - 10y + 12y + 12 - 9 = 0

-y² + 2y + 3 = 0

Change the sign of expression. because it helps to solve.

y² - 2y - 3 = 0

Splits the term -2y

y² + y -3y - 3 = 0

Factor out y from the first pair and -3 from second pair of expression.

y ( y + 1 ) - 3 ( y + 1) = 0

Factor out y + 1 from the expression.

( y + 1 ) ( y - 3 ). = 0

When product and factors equals 0. at least one factor is 0.

y + 1 =0

y - 3 = 0

Solve for y

y = -1 and y = 3

If we plug the 3 as y in the expression we find that y = 3 is the true solution of this expression.

This equation has one solution which is y = 3.

Key West, Florida to Seattle, Washington is 3,518 miles. If it
takes 51 hours to drive there, what is the average speed?

Answers

Answer:

69 miles/hour

Step-by-step explanation:

Average speed = Total distance travelled / Total time taken

Distance travelled = 3,518 miles

Time taken = 51 hours

Average speed = Total distance travelled / Total time taken

= 3,518 miles / 51 hours

= 68.980392156862

Approximately,

Average speed = 69 miles/hour

Answer: 69 miles/hour

Step-by-step explanation:

Pam laid three times as many tiles on Saturday as she laid on Sunday. If Pam laid 80 tiles over the weekend altogether, how many tiles did she lay on Saturday?

Answers

Answer:

Pam laid 60 tiles on Saturday and 20 on Sunday.

Step-by-step explanation:

Given that Pam laid three times as many tiles on Saturday as she laid on Sunday, if Pam laid 80 tiles over the weekend altogether, to determine how many tiles did she lay on Saturday the following calculation must be performed:

3X + X = 80

4X = 80

X = 80/4

X = 20

Therefore, Pam laid 60 tiles on Saturday and 20 on Sunday.

[tex] {2}^{x} - 3( {2}(^{x} + \frac{1}{2} )) + {2}^{2} = 0[/tex]
Can someone solve this equation?​

Answers

Answer:   [tex]\huge\boxed{x=log_2\frac{12\sqrt{2}+4}{17}}[/tex]

Step-by-step explanation:                                                                       [tex]\displaystyle\ \bigg{2^x-3(2^{x+\frac{1}{2} }})+2^2=0 \qquad ; \ \ \boxed{t=2^x} \\\\t-3t\sqrt{2} +4=0 \\\\ t(1-3\sqrt{2} )=-4 \\\\ t=\frac{4}{3\sqrt{2} -1} \cdot \frac{3\sqrt{2}+1 }{3\sqrt{2}+1 } =\frac{12\sqrt{2}+4}{17} \\\\\\2^x=\frac{12\sqrt{2}+4}{17} \\\\x=log_2 \ \ \frac{12\sqrt{2}+4}{17}[/tex]

One hundred rats are being trained to run through a maze and are rewarded when they run through it correctly. Once a rat successfully runs the​ maze, it continues to run the maze correctly in all subsequent trials. The number of rats that run the maze incorrectly after t attempts is given approximately by Find the number of trials required such that only ​% of the rats are running the maze incorrectly. Round to the nearest trial.

Answers

Answer:

6 trials

Step-by-step explanation:

The number of rats that run the maze incorrectly after t trials ;

N(t) = 100e^-0.14t

Initial number of rats = 100

45% of rats to run the maze incorrectly ; 45% * 100 = 45 rats

N(t) = 45

N(t) = 100e^-0.14t

45 = 100e^-0.14t

45/100 = e^-0.14t

0.45 = e^-0.14t

Take the In of both sides :

In(0.45) = In(e^-0.14t)

- 0.798507 = - 0.14t

Divide both sides by -0.14

- 0.798507 / - 0.14 = - 0.14t / - 0.14

5.7036 = t

To the nearest whole number :

Number of trials, t = 6 trials

PLEASE HELP ME ILL MARK YOU BRAINLIEST !!!!!!!!!!

Answers

Step-by-step explanation:

(1/2) / (1/3) = (1/2)(3/1) = 3/2 miles per hour = 1.5 miles per hour

Answer:

Step-by-step explanation:

to find the unit rate, which is what we are looking for, we have to divide the number of miles by the number of hours. Specifically:

[tex]\frac{\frac{1}{2} }{\frac{1}{3} }[/tex] and to work this out, we bring up the bottom fraction and flip it to multiply, giving us:

[tex]\frac{1}{2}[/tex] × [tex]\frac{3}{1}[/tex] which is [tex]\frac{3}{2}[/tex] miles per hour (which is the same thing as walking a mile and a half every hour). The choice you're looking for is the one that reflects 3/2 miles per hour. (I can't see which choice it is; they're too small!)

In the United States, among a representative group of 6,006 white men and 1,126 black men, ages 70-79 at diagnosis with stage IV prostate cancer, 2,337 white men and 344 black men developed a second cancer of some kind after 5 years of follow-up. What is the incidence of a second cancer in the white population

Answers

Answer:

White men diagnosed with stage IV prostatic adenocarcinoma within the age bracket of 70-79 are 1.27 times more likely to survive five years after the diagnosis of stage IV prostatic adenocarcinoma than black men.

Step-by-step explanation:

The exposure is race and the outcome is survival.  

Race   Alive    Dead           T

W       2337     3669         6006

B         344        782          1126  

Relative Risk -  1.27  

White men diagnosed with stage IV prostatic adenocarcinoma within the age bracket of 70-79 are 1.27 times more likely to survive five years after the diagnosis of stage IV prostatic adenocarcinoma than black men.

Which of the following is an even function?

Answers

Answer:

thats right

Step-by-step explanation:

odd functions are ones you flip 180 degrees and get same thing but basically everything else (unless of course it has no symmetry such as sqrt x) should be even (even can also be thought of as bilateral symmetry)

f(x)=3x^2 and g(x)=x+2 find (f.g)(x)

Answers

Answer:

3[tex]x^{3}[/tex] + 6[tex]x^{2}[/tex]

Step-by-step explanation:

(f · g )(x) = 3[tex]x^{2}[/tex] · (x + 2) = 3[tex]x^{3}[/tex] + 6[tex]x^{2}[/tex]  (Multiply the two terms by distributing)

Which is a simplified form of the expression -6a + 2(2a + 2)?
A.-2a + 4
B. -2a - 4
C. 2a + 4
D. 2a - 4

Answers

Answer:

-2a +4

Step-by-step explanation:

-6a + 2(2a + 2)

Distribute

-6a +4a +4

Combine like terms

-2a +4

Answer:

Answer A is correct

Step-by-step explanation:

First Solve the brackets

[tex] - 6a + 2(2a + 2) \\ - 6 a+ 4a + 4[/tex]

Then combine like terms

[tex] - 6 a+ 4a + 4 \\ - 2 a + 4[/tex]

B 2 -3 -2 -1 Use the Pythagorean theorem to find the distance between points A and B on each graph. round answers to the nearest tenth.​

Answers

hypotenuse= 9²

so the distance between the 2 points is 81

4²+5²=c²

factor out the square which gives (4+5)²=c²

which makes c=9

answer=81

Arc AC is adjacent to arc CD. If arc AC measures 35 degrees and arc CD measures 45 degrees, what is the measure of arc AD according to the Arc Addition Postulate?

Answers

Answer:

80°

Step-by-step explanation:

You just need to sum up the values according to arc addition postulate:

the measure of the arc formed by two adjacent arcs is the sum of the measures of the two arcsm(arc AD) = m(arc AC) + m(arc CD)m(arc AD) = 35° + 45° = 80°

Now we have to find,

The measure of arc AD according to the Arc Addition Postulate.

AD is the sum of the measures of the other two arcs. Then measure of AD is,

→ AC + CD

→ 35° + 45°

→ 80° (final answer)

Hence, the measure of arc AD is 80°.

Simplify
a)78.5÷3.14
b)56.272×41.2
c)4 4/7÷5 1/3

I need step by step explanation pls​

Answers

Answer:

[tex]78.5 \div 3.14 \\ = 25 \\ \\ 56.272 \times 41.2 \\ = 2318.4067 \\ \\ 44 \div 7 \div 51 \div 3 \\ = 0.04[/tex]

you have $9 and earn $0.50 for each cup of orange juice you sell. Write an equation that represents the total amount A (in dollars) you have after selling j cups of orange juice

Answers

Answer:

Hello there ,

The answer to this equation would be:

A=.50j+9

Step-by-step explanation:

this answer should be correct because he started with 9,

and he is selling each cup (j) for 0.50

Let me show you an example:

Ok lets say he sold 10 (j) cups:

you would replace the (j) with the 10

A=0.50(10)+6

A=5+6

A=11 and he would have $11

but that just an example so the real answer to your question is:

A=.50j+9

Hope this help. If correct please give brainliest.

Thank you,

Have a good day !!!!!

Monica purchased adult and youth tickets for the fair. She bought x adult tickets for $28 each and y youth tickets for $15. Write an expression that can be
used to show the total cost, C, of all tickets.
O C = (28 + 15)x
OC = (28 + 15)(x + y)
O C = 28x + 15y
O C = 28y + 15x

Answers

Answer: =28x + 15y

Step-by-step explanation:

What is the slope of the line? What is the y-intercept of the line? y = -x - 6

Answers

Answer:

m = -1

y intercept = -6

Step-by-step explanation:

The given equation of the line is ,

[tex]\implies y = -x -6[/tex]

We know that the Standard equation of Slope Intercept Form of the line is,

[tex]\implies y = mx + c[/tex]

Where ,

m is slope c is y intercept .

On comparing to the Standard form of the line we get ,

[tex]\implies Slope = -1 [/tex]

[tex]\implies y - intercept= -6 [/tex]

Answer:

Slope: -1

Solution:This equation is written in slope-intercept form (y=mx+b).In this formula, "m" stands for the line's slope and "b" stands for the y-intercept of the line.Also, please notice that the slope of the line is the coefficient of x (the number next to x)If we don't have a number next to x, then the coefficient is equal to 1.If we have a minus sign next to x, then the coefficient is equal to -1.Therefore, the slope of the line is -1.Now, the y-intercept is a constant that's subtracted from/added to the slope.Therefore, the y-intercept of the line is -6.

Hope it helps.

Do comment if you have any query.


Which step shows the result of applying the subtraction property of equality?
(12x+8)+4-3

Answers

Answer:

Value of expression = -3 / 4

Step-by-step explanation:

Given:

(12x + 8) + 4 = 3

Find:

Value of expression

Computation:

Given expression

(12x + 8) + 4 = 3

Step 1: Use Distributive property

12x + 8 + 4 = 3.

Step 2: By adding like terms.

12x + 12 = 3

Step 3: Transfer

12x = 3 - 12

Step 4: Subtract

12x = -9

Step 4: Divide both sides by 12

12x / 12 = -9 / 12

x = -3 / 4

Value of expression = -3 / 4

Anita and beth have the same number of trading cards. Anita gives 18 of her cards to beth. As a result, beth has twice as many card as anita does. How many cards did anita have before she gave some away.

Answers

Answer:

18

Step-by-step explanation:

if Anita and Beth had the same amount of trading cards this means they each had 18 cards so when Anita gave Beth her cards the number of cards Beth had have been diul ed meaning Beth now has 36 cards while Anita has non

What is the value of x?

Enter your answer in the box.

Answers

Answer:

12

Step-by-step explanation:

the angles on top of a line (or below a line) sum up to 180 degrees, as a line stands in that regard for a flip from left to right - which is a half circle or 180 degrees.

therefore, the sum of both angles must be 180.

10x - 20 + 6x + 8 = 180

16x -12 = 180

16x = 192

x = 12

Sorry just needed points

Someone please help me on this and please tell me the answer directly please !!

Answers

Answer:

HAVE A NİCE DAY

Step-by-step explanation:

GREETİNGS FROM TURKEY ¯ツ

For each calculation choose the correct answer written in standard form.
a) (7 * 10°) ~ (3 x 10?)
A
B
21 x 100 21 x 10
С
2.1 x 10"
D
2.1 x 10
b) (2 x 10°) = (4 x 102)
A
2 x 10
B
5 x 10
с
0.5 x 10
D
2 x 10

Answers

Answer:

Both the answers will be B

Please help! Find the length of side CD.

Answers

Answer:

The answer should be 6.63

Bd and bc form a right triangle with cd

Use the Pythagorean theorem

Cd = sqrt( 12^2 - 10^2)

Cd = sqrt( 144-100)

Cd = sqrt(44) = 2sqrt(11)

Can some help with this problem

Answers

Answer:

20 degrees.

Step-by-step explanation:

The interior angles of a triangle add up to 180 degrees. One of them, bottom right, is already shown as 70 degrees. You can find the bottom left angle by subtracting 110, the supplementary angle, from 180 (the number of degrees in a straight line). The top angle, 2x, is equal to 40 degrees. (180-70-70 = 40). 40/2 = x, so x = 20 degrees.

pls pls pls answer and pls dont use this post just for extra points i actually rly need help
:( please don't

Answers

Answer:

1/2

Step-by-step explanation:

Probability is equal to the amount of desirable outcomes divided by the total amount of outcomes. Each coin has two sides, and there are three of them. This accounts for a total of 2^3 or 8 outcomes. Now, we need to find the amount of outcomes where two or more coins land on heads. We can start by listing those possibilities: THH, HTH, HHT, and HHH. Notice that the first three are just three ways of rearranging the same result. We can see that there are four desirable outcomes. This means the probability is 1/2.

Ming drew the model below to represent the equation 24+12=_x(8+4) What is the missing value in Ming's equation?

Answers

Given:

The equation is:

[tex]24+12=\_\_\times (8+4)[/tex]

To find:

The missing value.

Solution:

We have,

[tex]24+12=\_\_\times (8+4)[/tex]           ...(i)

Taking left hand side, we get

[tex]24+12=3\times 8+3\times 4[/tex]

Taking 3 common, we get

[tex]24+12=3\times (8+4)[/tex]             ...(ii)

On comparing (i) and (ii), we get

Missing value = 3

Therefore, the missing value in the given equation is 3.

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