# Factoring using the GCD/GCF of an Expression

If the terms on the prior page had been in a polynomial expression, the GCDs you found could have been used to factor the expressions.

The GCD can be factored out of the expression such as the one below. This creates a second expression, equivalent to the first. In this case, the GCD is $$4x$$ .

$$4x+8x^2=4x(1+2x)$$

Try this: Factor the expression

$$3x^3y+6x^2 y^2$$

If the GCF is $$3xy$$ can you find the other factor?

Factoring is used to find the zeros of polynomials from quadratics to polynomials of much higher degrees. You are going to learn two strategies to factor quadratics. Before using these strategies, be sure  that the terms are in descending order and that the terms don’t have a GCF  that can be factored out of the expression.