Question

Supoose y varies directly with x. If y=6 when x=-2, find x when y=15

Answer 1

When y = 15, x = -5.

Explanation:

"y varies directly with x" signifies the linear relationship y = kx, where k is the constant of proportionality.

Substituting 6 for y and -2 for x into this equation yields the value of k:

6 = k(-2), or k = -6/2, or k = -3

Then the proportional relationship is y = -3x.

If y = 15, then we can write 15 = -3x, or x = -15/3, or x = -5.

When y = 15, x = -5.