Polynomial: $x^a$ Exponential: $a^x$

Factor theorem is when $A$ is a factor of $f(x)$ if $f(-a) = 0$.

Textbook Examples

Question 1: Prove $(x + 4)$ is a factor.

Because $f(-4) = 0$, $(x + 4)$ is a factor.

Question 2: Show that $x^3 + 2x^2 - 5x - 10 = (x + 2)(x^2 - 5)$ has $(x + 2)$ as a factor.

Because $f(-2) = 0$, $(x + 2)$ is a factor.