# How do you factor 15a+21?

May 2, 2016

$15 a + 21 = \textcolor{b l u e}{3 \left(5 a + 7\right)}$

#### Explanation:

The constants in the terms of the given expression have a common factor of $\textcolor{b l u e}{3}$

Once this factor has been extracted the remaining factor color(blue)(""(5a+7))
has no further sub-factors.