Question

If the value of “y” varies directly with “x” and y = -8 when x = 20, find “y” if x = -4.

Answer 1

Answer:

8

Step-by-step explanation:

Answer 2

Answer:

y = $\frac{8}{5}$

Step-by-step explanation:

Given y varies directly with x then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition y = - 8 when x = 20

k = $\frac{y}{x}$ = $\frac{-8}{20}$ = - $\frac{2}{5}$

y = - $\frac{2}{5}$ x ← equation of variation

When x = - 4, then

y = - $\frac{2}{5}$ × - 4 = $\frac{8}{5}$