Question

Variable y varies directly with variable x, and y = 4 when x = 7.

What is the value of x when y = 12?

Answer 1

Plug it in again:

y = kx

4 = k(7)

4 = 7k

Divide 7 to both sides, we get 4/7.

Now plug that back into the equation:

y = kx

y = 4/7k

Plug in 12:

12 = 4/7k

Divide 4/7 to both sides or multiply by 7/4.

Answer 2

Can you do that?

Answer 3

We're dividing:

(12) / (4/7)

or multiplying:

12 * 7/4

Answer 4

is it 21?\

Answer 5

Yep!

Answer 6

Thanks!