Question

Y is directionally proportional to x

When y = 21, x = 5
Write an equation for y in terms of x

Answer 1

y=21/5x

Explanation:

When y is 21, x is 5.

5(21/5)=21, so we have y=21/5x

Answer 2

y = 21/5x

Explanation:

y is directly proportional to x

y = kx

Find k constant.

21 = 5k

21/5 = k

Plug k as 21/5.

y = 21/5x