4x^3-4x^2-15x+18=0
potential rational zeros: 1,2,3,6,9,1/2, 1/4,3/2,3/4
f(x)= 4x^3-4x^2-15x+18
f(1)= 4-4-15+18
is not = 0
so u substitute f(x) with a potential rational zero until d equation equals zero.
then u divide synthetically
after u divide synthetically, u will end up with a linear equation
then u factorize and find your zeros...
