Focus D: Solving Polynomial Equations by Factoring
(x - 4)(x + 2) = 0.
Thus the equation is x2 -2x - 8 = 0.
In essence, without even realizing it, you used the Factor Theorem to find the solution. You knew that if x = 4 was a root of the equation, then
(x - 4) had to be a factor. Similarly, (x + 2) had to be a factor since x = -2 was a root.