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2 years ago

Find the solution of the system of equations. - 3x + 4y = 12 2.x + 2y = -22

Mathematics

1 answer:

Nikitich [7]2 years ago

8 0

Answer:

x = -8

y = -3

Step-by-step explanation:

So first you're going to want to get x or y by itself using elimination or substitution. I used elimination to get x by itself.

You can multiply the second equation (2x + 2y = -22) by -2 so you can eliminate the y's. When you multiply it, you get -4x - 4y = 44

Then, you can add -3x + 4y = 12 and -4x - 4y = 44. The y's cancel out to leave -7x = 56. Divide both sides by -7 to get x = -8.

Now, you can plug in -8 for x in either one of the equations. I plugged it into the second equation to make it 2(-8) + 2y = -22.

2 · -8 = -16.

-16 + 2y = -22. Add 16 to both sides to get 2y = -6. Divide both sides by to get y = -3.

Hope this helps! :)

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60points if you answer

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3 years ago

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JulijaS [17]

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3 years ago

What is 0.54 converted to a simplified fraction?

nadya68 [22]

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3 years ago

A cellphone company charges $60 for a cellphone and a monthly rate to use the phone.Regina will pay $1,140 for a 24-month cellph

Alinara [238K]

The monthly rate is $45 for this cellphone plan.

Step-by-step explanation:

Given,

Amount charged for cell phone = $60

Amount paid by Regina for 24 month plan = $1140

Number of months = 24

Let,

m be the monthly rate for cellphone plan

Number of months * Monthly rate + cellphone charges = Amount paid

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Dividing both sides by 24

$\frac{24m}{24}=\frac{1080}{24}\\m=45$

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Keywords: subtraction, division

Learn more about subtraction at:

#LearnwithBrainly

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3 years ago

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard devia

gtnhenbr [62]

Answer:

$n=(\frac{2.58(58.2)}{1})^2 =22546.82 \approx 22547$

So the answer for this case would be n=22547 rounded up to the nearest integer

Step-by-step explanation:

Let's define some notation

$\bar X$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=58.2$ represent the population standard deviation

n represent the sample size

$ME =1$ represent the margin of error desire

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =+1 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 99% of confidence interval now can be founded using the normal distribution. The significance would be $\alpha=0.01$ and the critical value $z_{\alpha/2}=2.58$ , replacing into formula (b) we got:

$n=(\frac{2.58(58.2)}{1})^2 =22546.82 \approx 22547$

So the answer for this case would be n=22547 rounded up to the nearest integer

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3 years ago