Question

X and y vary directly. When x is 5, y is -30. What is y when x is -3?

Answer 1

x/y=5/-30

-3/y=1/-6

y=18

Answer 2

Answer:

Step-by-step explanation:

Hi there! I'd love to help you out!

Direct variation equations can be written as:

y = kx     where "k" is a constant.

We usually have to solve for "k" first. It tell as that when y = 30 then x = 10. So we will plug these into the direct variation equation and solve for k:

30 = 10k

/10    /10

3 = k

So now we know "k" is 3. Our direct variation equation specific to this problem now looks like:

y = 3x

Now we can solve the final part. We will plug 84 in for y and solve for x:

84 = 3x

/3     /3

28 = x

We now know that when y = 84, x = 28. I hope this explanation was thorough and answered all of your questions. I specialize in assisting homeschool students and am a homeschool mom myself so feel free to reach out any time you have any questions! Learn on :)