Answer: When y = -4, x = -10.
Explanation:
The equation for direct variation is y = kx^n, where k is the constant of variation. n is the exponent above the x value, but since this problem doesn’t involve exponents greater than one, we can ignore it.
First, find k.
y = kx
6 = k*15
k = 6/15 or 2/5
Now, we can solve for any x or y input. Let’s find x when y = -4.
y = kx
-4 = 2/5 * x
(to cancel out the fraction, multiply each side of the equation by its reciprocal, 5/2)
x = -4 * 5/2
x = -20/2
x = -10
