Question

Suppose y is directly proportional to x and that y = 40 when x=5.
Complete parts (a)and(b).

Find the constant of proportional k.
k=

(b)use y=ky to find y when x=9
y=

Answer 1

I'm amazed! You're a college student and don't know the difference between a school and a school subject?

Answer 2

40 = 5 k
so
k = 8

y = 8 x

y(9) = 8*9 = 80 - 8 = 72