Can someone check tell me why 1) is correct and why 2) is incorrect?!

Willing to give brainliest

Step-by-step explanation:

I recommend you to use matrices for systems of equations; it's a lot faster and more expedient.

Answer:

[tex](2, -1)[/tex]

Step-by-step explanation:

Given the system of equations:

[tex]\begin{cases}5x+7y=3,\\2x+3y=1\end{cases}[/tex]

Multiply the first equation by -2 and the second equation by 5, then add both equations to solve for [tex]y[/tex]:

[tex]\begin{cases}-2(5x+7y)=(-2)3,\\5(2x+3y)=(5)1\end{cases},\\\begin{cases}-10x-14y=-6,\\10x+15y=5\end{cases},\\-10x+10x-14y+15y=-6+5,\\y=-1[/tex]

Substitute [tex]y=-1[/tex] into any equation to solve for [tex]x[/tex]:

[tex]2x+3y=1,\\2x+3(-1)=1,\\2x-3=1,\\2x=4,\\x=\boxed{2}[/tex]

Therefore, the solution to this system of equations is [tex]\boxed{(2, -1)}[/tex]

Answer:

x = [tex]\sqrt{26}[/tex]

Step-by-step explanation:

using pythagoras theorem

here [tex]\sqrt{13}[/tex] and [tex]\sqrt{13}[/tex] are the legs of the right angled triangle and x is hypotenuse.

a^2 + b^2 = c^2

[tex](\sqrt{ 13 })^2 + (\sqrt{13})^2 = x^2[/tex]

13 + 13 = x^2

26 = x^2

[tex]\sqrt{26}[/tex] = x

Answer:

answer would be c

Step-by-step explanation:

hope this helps

Answer:

364 messages

Step-by-step explanation:

The king uses 14 flags in all and arranged 3 at a time to send a code to his general. The number of coded messages that can be sent by the king can be determined by;

Total number of colored flags = 14

Number of flags arranged per time = 3

So that,

[tex]^{14} C_{3}[/tex] = [tex]\frac{14!}{(14 - 3)!3!}[/tex]

       = [tex]\frac{14!}{11!3!}[/tex]

       = [tex]\frac{14*13*12*11!}{11!3!}[/tex]

       = [tex]\frac{14*13*12*11!}{11!3*2!}[/tex]

       = 364

[tex]^{14} C_{3}[/tex] = 364

The number of coded messages that can be sent by the king is 364.

Answer:

cos(2π/35)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Pre-Calculus

Step-by-step explanation:

Step 1: Define

Identify

cos(π/5)cos(π/7) + sin(π/5)sin(π/7)

Step 2: Simplify

Answer:

8.

a) f'x means you find the derivative.

2 * d/dx x^2 -b * d/dx x + d/dx c

use power rule x^2 = 2x^1

2*2x = 4x.  the derivative of the differentiation variable, x is 1 and the derivative of a constant, c is 0

4x-b+0

4x-b is our derivative

(I am still figuring out b and c, I will edit this answer and put the solution for b and c.)

Step-by-step explanation:

Answer:

I assume that this is a math question not a chemistry question...

In math I assume the answer is 1 liter....

total = 2 liters (1 liter water 1 liter ammonia )

If this is a chemistry question there is a difference between total

volume, and total weight, which would not result in the answer being 1 liter

Step-by-step explanation:

Answer:, Joey will pay $117.18 for sneakers.

Step-by-step explanation:

Given: original price = $155

Discount rate = 30%

Tax rate = 8%

Price after discount = Original price - (Discount) x (original price)

[tex]= 155-0.30\times 155\\\\=155-46.5\\\\=\$\ 108.5[/tex]

Tax = Tax rate x (Price after discount)

[tex]= 0.08 \times 108.5[/tex]

= $ 8.68

Final price for sneakers = Price after discount + Tax

= $ (108.5+8.68)

= $ 117.18

Hence

Answer:it is the number above the 5

Step-by-step explanation:

Answer:

log10( 5x^2)

Step-by-step explanation:

2 log10 (x) + log10 (5)

we know that  c loga (b) = log a (b^c)

log10 x^2 + log10 (5)

We also know that logc a + logc b = logc (ab)

log10 (x^2* 5)

log10( 5x^2)

Answer:

- 3

Step-by-step explanation:

let n be the number , then

3n + 4 = n - 2 ( subtract n from both sides )

2n + 4 = - 2 ( subtract 4 from both sides )

2n = - 6 ( divide both sides by 2 )

n = - 3

The number is - 3

The number is - 3.

To find the number.

What is integer?

An integer is a whole number (not a fractional number) that can be positive, negative, or zero. All the whole numbers are also integers, because integers include all the positive and negative numbers.

Given that:

let n be the number , then

3n + 4 = n - 2 ( subtract n from both sides )

2n + 4 = - 2 ( subtract 4 from both sides )

2n = - 6 ( divide both sides by 2 )

n = - 3

So, the number is - 3.

Learn more about integer here:

https://brainly.com/question/24145706

#SPJ2

Answer:

119.32 m

Step-by-step explanation:

The circumference of a circle is given by

C = 2*pi*r

C = 2 (3.14) *19

C = 119.32

Answer:

the answer is 110 degrees because 50 plus 20 is 70 and a triangle is 180 degrees so you do 180 minus 70 which gives you 110 :)

Step-by-step explanation:

Answer:

[tex]x^{2}[/tex]

Step-by-step explanation:

Answer:

There are 24 different correspondences.

Step-by-step explanation:

A one-to-one correspondence means that each element of A can be mapped into only one element of B, and we can't have two or more elements from A mapped into one element from B.

So, to count all the possible combinations, we need to find the number of possible options for each mapping

The first element from A, the 1, can be mapped into any of the four elements of B, so here we have 4 options.

The second element from A, the 2, can be mapped into any of the remaining elements from B, 3 of them (remember that one of the elements of B is taken).

The third element from A, the 3, can be mapped into any of the remaining elements from B, 2 of them now, so here we have 2 options.

The final element from A, the 4, can be mapped into the remaining element from B, so here we have only one option.

The total number of different correspondences (or combinations) is equal to the product between the numbers of options, this is:

Combinations = 4*3*2*1 = 12*2 = 24

There are 24 different correspondences.

Answer:

$8.00

$32.00

$62.000

N.$6.00 + $2.00

Step-by-step explanation:

Answer:

C. Yes, 3.5.

Step-by-step explanation:

If there is a relationship of direct proportionality for every ordered pair of the table, then the constant of proportionality must the same for every ordered pair. The constant of proportionality ([tex]k[/tex]) is described by the following expression:

[tex]k = \frac{y}{x}[/tex] (1)

Where:

[tex]x[/tex] - Input.

[tex]y[/tex] - Output.

If we know that [tex](x_{1}, y_{1}) = (13, 45.5)[/tex], [tex](x_{2}, y_{2}) = (14, 49)[/tex] and [tex](x_{3}, y_{3}) = (15, 52.5)[/tex], then the constants of proportionalities of each ordered pair are, respectively:

[tex]k_{1} = \frac{y_{1}}{x_{1}}[/tex]

[tex]k_{1} = \frac{45.5}{13}[/tex]

[tex]k_{1} = \frac{7}{2}[/tex]

[tex]k_{2} = \frac{y_2}{x_2}[/tex]

[tex]k_{2} = \frac{49}{14}[/tex]

[tex]k_{2} = \frac{7}{2}[/tex]

[tex]k_{3} = \frac{y_{3}}{x_{3}}[/tex]

[tex]k_{3} = \frac{52.5}{15}[/tex]

[tex]k_{3} = \frac{7}{2}[/tex]

Since [tex]k_{1} = k_{2} = k_{3}[/tex], the constant of proportionality is 3.5.

Answer:

C

Step-by-step explanation:

Answer:

A

Step-by-step explanation:

The sequence of payment is geometric , that is

1, 3, 9, ...

The sum to n terms of a geometric sequence is

[tex]S_{n}[/tex] = [tex]\frac{a(r^{n}-1) }{r-1}[/tex]

where a is the first term and r the common ratio

Here a = 1 and r = 3 ÷ 1 = 3 , then

[tex]S_{15}[/tex] = [tex]\frac{1(3^{15}-1) }{3-1}[/tex] = [tex]\frac{14348907-1}{2}[/tex] = [tex]\frac{14348906}{2}[/tex] = 7174453 cents and

7174453 ÷ 100 = $71,744.53 → A

Step-by-step explanation:

3a-26

3(5)-26

15-26

=-11

Answer:

[tex]3a - 26 \\ 3 \times 5 - 26 \\ 15 - 26 \\ = - 11[/tex]

Answer:

x= -1 or x= 5/3

Step-by-step explanation:

3x²–2x=5​

3x²-2x-5=0

(3x+_)(x-_)

(3x-5)(x+1)

(I just use a guess and check method to see what will fill the blanks and let the expression expand to become 3x²–2x=5​)

3x-5=0

3x=5

x= 5/3

x+1

x=-1

x= -1 or x= 5/3

Hope this helps!

Answer:

0.17

Step-by-step explanation:

im not really sure but that closest as 0.75+0.6+0.2=0.83 and 1.00-0.83=0.17

Answer:

0.17

hope this helps

Answer:

B. y= -2x +2

Step-by-step explanation:

the slope is negative 2 and the point where the line crosses the y-int is 2

Problem 35

The bar graph is shown below

You simply draw various rectangles such that the heights represent the frequency of each animal type.

Eg: there are 20 elephants, so the "elephant" bar is 20 units tall.

You can make the bar graph by hand, or use spreadsheet software. I recommend going with software (if you can).

=======================================================

Problem 36

1 book = 20 mm thickness

5 books = 5*20 = 100 mm thickness

1 paper = 0.016 mm thickness

5 papers = 5*0.016 = 0.08 mm thickness

total thickness = 100+0.08 = 100.08 mm

=======================================================

Problem 37

121/11 = 11

121 = 11*11

If we say 11+11+11+...+11, and have 11 copies of these values added, then we get to a sum of 121

This is probably the easiest way to get the answer assuming repeated values are allowed.

You can stop here if your teacher allows you to use repeated values. If not, then move onto the next section.

-----------

If your teacher requires you to add 11 different numbers, then you can follow this procedure

After carefully following those steps, you'll get this sequence (in the exact order shown):

{9, 7, 5, 3, 1, 11, 21, 19, 17, 15, 13}

There are three properties to notice of this sequence

That sequence we got sorts to {1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21}

and we can say 1+3+5+7+9+11+13+15+17+19+21 = 121

Answer:

3 1/3

Step-by-step explanation:

5/2 divided by 3/4 = 3 1/3

Answer:

x-1= -18

x = -18 +1

x = -17

2x - 4 = - 38

2x = -38 + 4

2x = -34

x = -34/2

x = -17

Step-by-step explanation:

Answer:

24 Miles

Step-by-step explanation:

We multiply:

40 * 0,6 = 24 miles

f(2) = -3

Step-by-step explanation:

f(x) = x - 5

f(2)) = (2) - 5 = -3

Answer:

A

Step-by-step explanation:

i don't know the real answer but i have learned it before so it's an educated guess

Answer:

greatest 9776410 smallest 1046779

Step-by-step explanation:

in smallest we cannot write 0 first because 0 has no units

Answers:

Largest possible = 9776410

Smallest possible = 1046779

====================================================

Explanation:

To make the greatest 7-digit number, we start with the largest digit at the left-most end. So we start with 9. Then the next digit is the next largest, which is 7, and so on until we get

9776410

If we swap any two distinct digits, then we'll get something smaller than that value above. For instance, swap the 1 and 0 which leads to 9776401 and this is smaller than 9776410. This is simply because 01 is smaller than 10. Every other digit is kept the same. Try out other digit swaps to see that the result is smaller than the value in bold.

------------------------

To make the smallest 7-digit number, we just take the idea mentioned in the first section and we reverse it. We start with the smallest digit. We can't have 0 as the first value or else it won't be a 7-digit number. So we go for 1 instead. Then we can pick 0 next. For the third digit we pick the third smallest (the digit 4), and we build up to get

1046779

If we swap any distinct two digits, then we'll get something larger than this value. Let's say we swap the second 7 and the 9 at the end. We go from 79 at the end to 97. Since 79 < 97, this means 1046779 < 1046797. That's one example of many.

--------------------------

So in short, the largest number possible has all the largest digits to the left (and we decrease going left to right). The smallest number possible is the reverse of this having the smallest digits to the left (then increasing from left to right). The 0 cannot be at the left-most digit position, or else won't have a seven digit number.

Answer:

Angle A = 19

Step-by-step explanation:

Vertical angles are congruent ( equal to each other )

If angle A and angle B are vertical angles and vertical angles are congruent then angle A = angle B

If angle A = 3x + 13 and angle B = 5x + 9 then 3x + 13 = 5x + 9

( Note that we just created an equation that we can use to solve for x )

We now solve for x using the equation created

3x + 13 = 5x + 9

Step 1 subtract 3x from both sides

Outcome: 13 = 2x + 9

Step 2 subtract 9 from both sides

Outcome: 4 = 2x

Step 3 divide both sides by 2

Outcome: x = 2

Now to find Angle A

All we have to do to find the measure of angle a is simply substitute 2 for x in it's given expression ( 3x + 13 )

Substitute 2 for x

Angle A = 3(2) + 13

Multiply

Angle A = 6 + 13

Add

Angle a = 19

Answer:

additive inverse properties