Question

What is the direct variation equation if y varies directly with x and y = –9 when x = –45?

a. y = 1/5x

b. y = -5x

c. y = 5x

d. y = -1/5x

Answer 1

Direct variation equation is y = kx ; k is the constant of variation.

y = -9
x = -45

-9 = k(-45)
-9/-45 = k
1/5 = k

y = 1/5x  CHOICE A.