Question

When y is directly proportional to x, the value of y = -2 when x = 4. What is the value of y when x = 8?

Answer 1

y = -4

Explanation:

When y is directly proportional to x,

= y ∝ x

= y = kx

Finding k

the value of y = -2 when x = 4

-2 = k4

k = -2/4

k = -1/2

. What is the value of y when x = 8

Finding y

y = kx

y = -1/2 × 8

y = -4