Question

What is the direct variation equation if f(x) varies directly with x and f(x)=−18 when x = 3?

A) f(x)=−15x
B) f(x)=−3x
C) f(x)=−16x
D) f(x)=−6x

Answer 1

your answer is B becausewe can find k when given any point by dividing the y-coordinate by the x-coordinate. For example, if y varies directly as x, and y = 6 when x = 2, the constant of variation is k = - 3.