Question

(r-3)(r+6)=0

Answer 1

It is already factored.
So, either r - 3 = 0
r = 3

-OR-

r + 6 = 0
r = -6

Possible solutions for r are (3,-6)

Answer 2

r(r+6)-3(r+6)
r^2+6r-3r-18=0
r^2+3r-18=0