Question

Suppose that y is directly proportional to x.
If y = 10 when x = −5, what is the value of y when x = 30?

Answer 1

"y is directly proportional to x" --- y = kx , where k is a constant
for the given:
10 = -5k
k = -2

so y = -2x is your equation:

so when x = 20 , y = ......

Answer 2

sym