Question

The values of x and y vary directly

and one pair of values are given.
Write an equation that relates x
and y. Simplify completely.
x = 12, y = 3
(It’s a fraction answer)

Answer 1

The general formula is x=4y

Explanation:

x varies directly as y

x∝y

Then, let k be constant of proportionality

x=ky

If x=12 and y=3

Then, 12=3k

Divide both side by 3

k=4

The general formula

x=ky

Then, since K=4

x=4y

Answer 2

y = (1/4)x

Explanation:

"Direct variation" here signifies y = kx, where k is the constant of proportionality.

Then y = kx. Here we are to find k using the info that x = 12 and y = 3:

3 = k(12), or

k = 3/12, or k = 1/4

Then y = (1/4)x