# Multiplying a Trinomial by a Binomial

In this video, we are going to look at how to multiply a trinomial by a binomial.
For example:
To multiply $(x+3)(x^2+2x-5)$ we have to distribute each term in the binomial to each term in the trinomial.
When we distribute the x to the terms in the trinomial, we get $x^3$, $2x^2$, and $-5x$. When we distribute the 3 to the trinomial, we get $3x^2$, $6x$, and $-15$. So now we are left with
$x^3+2x^2-5x+3x^2+6x-15$
From here, we want to combine like terms, to give us a final answer of
$x^3+5x^2+x-15$

• ## Want full access to all of our free math tutorials & practice problems?

Used by students across the country. Pre-Algebra, Algebra I, Geometry, & Algebra II