Suppose that y is directly proportional to x. If y = 10 when x = −2, what is the value of y when x = 15?

Question

Not sure what to do here.

I think it's something to do with a constant?

Answer 1

y =kx

10 = -2k

k = -5 = the constant of proportionality

y =-5x

y = -5(15) = -75 when x =15