Question

it is given that y varies directly as (ax-4) where a is a non zero constant.y=16 when x=4 and y=34 when x=7, find the value of a

Answer 1

y = k(ax-4)
y = 16 when x=4:
16=k(a*4-4)

Answer 2

y=34 when x=7:
34=k(a*7-4)

Answer 3

Solve the system of equations:
16=k(4a-4)
34=k(7a-4)
That will get you your answer.

Answer 4

thank you~