Question

1. Suppose y varies directly with x, and y = 14 when x = –4. What is the value of y when x = –6?

Answer 1

1) y varies directly with x, then we have: y = kx,  k is the constant of variation 

y = kx

14 = - 4k
k = 14/- 4, or - 7/2, or - 3.5 

y = kx
y = - 3.5(- 6) 
y=21

2) 201.6 is the right answer.see the procedure used in Q1.

3) K = y/x
        = 9/12
        = 3/4