where f(x)=0 is the zeros of the funciton
factor out the common factor of all of them which is 9x
f(x)=9x(x^2+2x-15)
what 2 numbers multiply to get -15 and add to get 2?
5 adn -3
f(x)=(9x)(x+5)(x-3)
set to zero
9x=0
x=0
x+5=0
x=-5
x-3=0
x=3
zeroes at x=-5, 0,3
