Question

Y varies directly as x. If y=4 when x=16 find x when y = -2

Answer 1

-8 = x

Explanation:

"y varies directly as x" translates into y = kx, where k is the constant of proportionality.

We are told that when x = 16, y = 4. Thus, 4 = k(16), and k = 1/4.

Then y = (1/4)x.

If y = -2, what is x? -2 = (1/4)x.

Multiplying both sides by 4 eliminates the fraction:

-8 = x

Answer 2

X becomes 4

Explanation:

The function is
`x^(2) = y`

so

-2 x -2 = 4