Question

Assume that y varies directly with x, then solve. If y=-18 when x-6, find x when y=6. x=[?]

Answer 1

If y varies directly with x then it should satisfy the equation y = mx ----------> (1)

Substitute y = -18 and x = 6 in Eq (1)

-18  =  m (6)

m  =  (-18) / 6

m  =  - 3

Substitute y = 6 and m = -3 in Eq (1)

6  =  6 / (-3)

x  =  - 2

Answer :

x  =  - 2.