Question

If y varies directly as x, and y is 6 when x is 72, what is the value of y when x is 8?'

Answer 1

@Vocaloid

Answer 2

direct variation takes the form y = kx
if y = 6 and x = 72, what is k?

Answer 3

1/9!

Answer 4

not quite

6 = 72k
what is k?

Answer 5

need to get some sleep, @dan815 would you mind taking over? I think they've got a few more questions after this one

Answer 6

To find k, we need to get k by its self and we do that by dividing by 72 on each side of the equal sign.

6 = 72k
6 / 72 = 72k /72
6 / 72 = k
1 /12 = k
k = 1 /12

Now that we found k (our constant of variation ) we can solve for "what is the value of y when x is 8"

y = xk
y = 8 * (1 / 12)
y = 2/3