In order to solve the following system of equations by elimination, which process creates opposite coefficients to eliminate the y variable?

2x + y = 5
x + 4y = -7


A. Multiply the first equation by 4

B. Multiply the second equation by 2

C. Multiply the first equation by -4

D. Multiply the second equation by -2

Answer:

  h = 2.5

Step-by-step explanation:

Continue the solution by subtracting 250 from both sides.

  250 -250 +20h = 300 -250

  20h = 50

Divide both sides by 20

  20h/20 = 50/20

  h = 5/2 = 2.5

Step-by-step explanation:

The Pythagorean theorem is:

[tex] {c}^{2} = {a}^{2} + {b}^{2} [/tex]

where c is the hypotenuse.

The two wires in the sketch are the hypotenuse so we just use the formula

let the wires=x

So:

[tex] {x}^{2} = {12}^{2} + {6}^{2} [/tex]

[tex] {x}^{2} = 144 + 36[/tex]

[tex] {x}^{2} = 180[/tex]

[tex]x = \sqrt{180} [/tex]

[tex]x = 13.42[/tex] feet

Using the z-distribution, it is found that the p-value is of 0.5975.

At the null hypothesis, it is tested if the proportions are equal, that is, their subtraction is 0, hence:

[tex]H_0: p_1 - p_2 = 0[/tex]

At the alternative hypothesis, it is tested if they are different, that is, their subtraction is not 0, hence:

[tex]H_1: p_1 - p_2 \neq 0[/tex]

The sample sizes and proportions are given by:

[tex]n_1 = 631, p_1 = \frac{133}{631} = 0.2108[/tex]

[tex]n_2 = 121, p_2 = \frac{23}{121} = 0.1901[/tex]

The standard errors are given by:

[tex]s_1 = \sqrt{\frac{0.2108(0.7892)}{631}} = 0.0162[/tex]

[tex]s_2 = \sqrt{\frac{0.1908(0.8092)}{121}} = 0.0357[/tex]

For the distribution of differences, the estimate and the standard error are:

[tex]\overline{p} = p_1 - p_2 = 0.2108 - 0.1901 = 0.0207[/tex]

[tex]s = \sqrt{s_1^2 + s_2^2} = \sqrt{0.0162^2 + 0.0357^2} = 0.0392[/tex]

The test statistic is given by:

[tex]z = \frac{\overline{p} - p}{s}[/tex]

In which [tex]p = 0[/tex] is the value tested at the null hypothesis.

Then:

[tex]z = \frac{\overline{p} - p}{s}[/tex]

[tex]z = \frac{0.0207 - 0}{0.0392}[/tex]

[tex]z = 0.528[/tex]

Using a z-distribution calculator, with a two-tailed test, as we are testing if the mean is different of a value, the p-value is of 0.5975.

A similar problem is given at https://brainly.com/question/25869410

Answer:

[tex] \frac{1}{4} [/tex]

[tex] \frac{1}{3} [/tex]

Answer:

20 inches

Step-by-step explanation:

Use the Pythagorean Theorem.

[tex]a^2 + b^2 = c^2\\15^2 + b^2 = 25^2\\225 + b^2 = 625\\b^2 = 400\\b = \sqrt{400} \\b = 20[/tex]

Answer:

Some solutions of 9x−2y=18 are x=5 =−18 ; x=7 and y=19 ; x=9 and y=0 ; x=11 and y=9 and x=13 and y=18 .

Step-by-step explanation:

Answer:

96 oz

Step-by-step explanation:

1 lb= 16 oz

so, 16×6=96

Answer:

x = 20°

Step-by-step explanation:

OA = OB

so 140°+x°+x° = 180°

140+2x = 180

2x = 40

x = 20°

Answer:

6z+12

Step-by-step explanation:

you distribute it

The solution to the system of equations expressed as a coordinate point is [tex](x.y)=(-1,1)[/tex]

To solve the system

[tex]3x + y = -2\\y = 2x + 3[/tex]

Note that [tex]y[/tex] is already made subject of formula in [tex]y = 2x + 3[/tex]. So substitute the value for [tex]y[/tex] into [tex]3x + y = -2[/tex] to eliminate [tex]y[/tex] and leave us with an equation with [tex]x[/tex]

[tex]3x + y = -2\\3x + (2x+3) = -2\\3x+2x+3=-2\\3x+2x=-2-3\\5x=-5\\\frac{5x}{5}=\frac{-5}{5}\\x=-1[/tex]

Substitute this value of [tex]x[/tex] into [tex]y = 2x + 3[/tex] to get the value of [tex]y[/tex]

[tex]y = 2(-1) + 3\\y=-2+3\\y=1[/tex]

The solutions are [tex]x=-1,y=1[/tex], or expressed as a coordinate point

[tex](x.y)=(-1,1)[/tex]

Learn more about systems of equations here: https://brainly.com/question/16763389

Answer:

Its D. 36

Step-by-step explanation:

The sample sizes are quite large, so the central limit theorem applies. (It typically does as soon as the sample size exceeds 30 or so.) This means that the sample mean will be approximately normally distributed with the same mean 22 but standard deviation 3.1/√40 ≈ 0.4902.

Now, if the question is asking about the probability of the sample mean being an exact number, that probability would be zero.

But if you meant to ask something else, like "what is the probability that the sample mean is less than 21?" then we would have a non-zero probability. In this particular case, if Y is a random variable for the sample mean, then

Pr[Y < 21] = Pr[(Y - 22)/(3.1/√40) < (21 - 22)/(3.1/√40)]

… ≈ Pr[Z < -2.0402]

… ≈ 0.0207

Answer:

16feet

part B is 18 feed for a good at a better than the price but the one

666666666666666666766666666

Answer:

c

Step-by-step explanation:

i saw the answer sheet :)

Answer:

Step-by-step explanation:

Use law of cosines

c² = a² + b² - 2abcosθ

cosθ = (c² - a² - b²) / -2ab

c = length of AC = √(8 - 5)² + (4 - (-5))² = √90

b = length of AB = √(8 - 6)² + (4 - 3)² = √5

a = length of BC = √(6 - 5)² + (3 - (-5))² = √65

cosθ = (√90² - √65² - √5²) / -2√65√5

cosθ = 20 / -36.05551...

cosθ = - 0.5547001

θ = 123.69°

Answer: The answer is 8.91.

Answer : 8.91

Step - by - step explanation :

Sometimes if a question is to big for you - it's best to start off small . . .

4.60 + 3.28 = 7.88

7.88 + 1.03 = 8.91

Answer:

[tex]x=-1,1,-\sqrt{\frac{7}{4} },\sqrt{\frac{7}{4}}[/tex] and [tex]y=-1,\frac{1}{2}[/tex]

The ordered pair solutions are [tex](-\sqrt{\frac{7}{4}},0.5)[/tex], [tex](\sqrt{\frac{7}{4}},0.5)[/tex], [tex](-1,-1)[/tex], and [tex](1,-1)[/tex].

Step-by-step explanation:

I'm assuming the system is [tex]\left \{ {x^2+y^2=2} \atop {y=2x^2-3}} \right.[/tex]:

[tex]x^2+y^2=2[/tex]

[tex]x^2+(2x^2-3)^2=2[/tex]

[tex]x^2+(4x^4-12x^2+9)=2[/tex]

[tex]x^2+4x^4-12x^2+9=2[/tex]

[tex]4x^4-11x^2+9=2[/tex]

[tex]4x^4-11x^2+7=0[/tex]

[tex]x^4-11x^2+28=0[/tex]

[tex](x^2-7)(x^2-4)=0[/tex]

[tex](4x^2-7)(x^2-1)=0[/tex]

[tex]4x^2-7=0[/tex]

[tex]4x^2=7[/tex]

[tex]x^2=\frac{7}{4}[/tex]

[tex]x=\pm\sqrt{\frac{7}{4}}[/tex]

[tex]x^2-1=0[/tex]

[tex]x^2=1[/tex]

[tex]x=\pm1[/tex]

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

[tex]y=2(\pm\sqrt{\frac{7}{4}})^2-3[/tex]

[tex]y=2({\frac{7}{4}})-3[/tex]

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

[tex]y=\frac{1}{2}[/tex]

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

[tex]y=2(\pm1)^2-3[/tex]

[tex]y=2(1)-3[/tex]

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

[tex]y=-1[/tex]

Therefore, [tex]x=-1,1,-\sqrt{\frac{7}{4} },\sqrt{\frac{7}{4}}[/tex] and [tex]y=-1,\frac{1}{2}[/tex]

The ordered pair solutions are [tex](-\sqrt{\frac{7}{4}},0.5)[/tex], [tex](\sqrt{\frac{7}{4}},0.5)[/tex], [tex](-1,-1)[/tex], and [tex](1,-1)[/tex].

Step-by-step explanation:

let's think this through.

train a goes from A to B in 6 hours. that means with a speed of 1/6 / hour.

train b goes from B to A in 3 hours, so it is twice as fast as train a = 2/6 / hour.

when train b leaves B (at 7pm), train a was already traveling for 2 hours (1/3 of the whole trip) leaving it with 4 hours to go (2/3 if the distance).

that means that at that point now both trains are moving against each other with a relative speed of 3 times the

speed of a (the original speed of a plus the double speed of b).

this is the same as one train standing, and the other going the whole distance with 3 times the speed of a.

the whole distance is 2/3 of AB.

the speed is 3/6 / hour = 1/2 / hour.

so, a single train with that speed would cover the total distance AB in 2 hours. or half of the distance in 1 hour.

the question now, how long for 2/3 of AB.

the distances relate by a factor :

1/2 × f = 2/3

f = 2/3 / 1/2 = 2/3 × 2/1 = 4/3

now we need to multiply also the time in the distance/time speed ratio by this factor.

therefore, 2/3 of the total distance is done in 1×4/3 = 4/3 of an hour.

that means both trains meet after 4/3 of an hour after 7pm.

that is 7pm plus 1 hour and 20 minutes giving us 8:20pm.

Answer:

x=20

Step-by-step explanation:

Answer:

x=  47 18+2  201  i  ≈0.382978723+0.603295612i x=  47 −2  201  i+18  ≈0.382978723−0.603295612i  Hopefully this makes just the same amount of sense as this question

x = 27

Step-by-step explanation:

The two angles shown are called co-exterior angles and by definition, their sum is equal to 180° so we can write

[tex](3x - 3) + (4x - 6) = 180[/tex]

[tex]\Rightarrow 7x - 9 = 180[/tex]

Simplifying this further, we get

[tex]7x = 189 \Rightarrow x = 27[/tex]

Answer:

The gradient is negative.

Step-by-step explanation:

The gradient represents the rise/run ratio. Always read the line's path left to right, and if it goes up, then it is positive, down means negative gradient, and if it doesnt move then it 0. It is undefined if the line is vertical.

Answer:

ok ok ok ok ok

Step-by-step explanation:

Answer:

ok?

Step-by-step explanation:

b r = 178 + h;

b r + h = 676;

then, 178 + 2h = 676 => h = 498/2 = 249 => b r = 178 + 249 = 427

Answer:

676

Step-by-step explanation:

h=b+178=427

b=b=249

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

(b+178)+b=676

2b+178=676

2b=498

b=249

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

249+427=676

Kaneppeleqw and 2 more u

The change in air temperature over 1.25 hours is -9.75°F

A linear equation is in the form:

y = mx + b;

where y, x are variables,  m is the rate of change and b is the initial value of y.

As a hurricane approaches, the air temperature changes −7.8°F every hour. The amount of change after 1.25 hours is:

Change = −7.8°F every hour * 1.25 hours

Change = -9.75°F

Therefore the change in air temperature over 1.25 hours is -9.75°F

Find out more on linear equation at: https://brainly.com/question/14323743

Answer:

15

Step-by-step explanation:

25/5 = 5.

3 x 5 / 5+5+5 = 15

15/25 = 3/5

Answer:

Step-by-step explanation:

if x is the number of times you go swimming

100 + 4x < 6x

Out of an 98 day season

If you attend 50 days, the cost is $300 either with or without the membership

Less than 50 days, it's less expensive to just pay the daily rate.

More than 50 days, it's less expensive to have the membership.

Answer:

B)

Step-by-step explanation:

2(n+7)+3n

now you multiply 2 though

2n+14+3n

Add common factors

5n+14

__________________________________________________________

Hope this helps!!

If I am wrong, please tell me, I enjoy learning from my mistakes:)

Answer:

7.44miles

Step-by-step explanation:

1km = 0.62miles

12km will be ; 0.62 × 12

= 7.44miles

The decrease is  (95-68) = 27 .

As a fraction, the decrease is  27/95  of the original amount.

To change any fraction to a decimal, do the division:

                            (27)  divided by  (95) = 0.2842...

To change any decimal to a percentage, move the

decimal point two places that ==> way:

                            0.2842...  =  28.42... %Answer:

Step-by-step explanation:

[tex]\qquad[/tex]☀️ At first we need to find out the difference between 95 and 68.

[tex]\qquad[/tex][tex] \sf \longrightarrow 68 -95 \\[/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow -27[/tex]

[tex]\qquad[/tex]☀️ Now, divide the number by "the starting number.

[tex]\qquad[/tex][tex] \sf \longrightarrow \dfrac{-27 }{97}[/tex]

[tex]\qquad[/tex][tex] \sf \longrightarrow -0.2842[/tex]

[tex]\qquad[/tex]☀️ And finally, we have to multiply the result by 100 to get it in terms of percent.

[tex]\qquad[/tex][tex] \sf \longrightarrow -0.2842 \times 100[/tex]

[tex]\qquad[/tex][tex] \red{\bf \longrightarrow -28.42℅}[/tex]

[tex]\qquad[/tex]_________________________