You don't actually need 3 terms to solve equations. Start by using the greatest common factor (GCF) of x to simplify things.
x(x - 12) = 0 GCF of x pulled out
x = 0 x - 12 = 0 setting both sections equal to 0 to solve
x = 0 x = 12 solving for x
2 solutions for this problem:
x = 0, 12