# How do you factor 3a+3b+ab+b ^2?

Starting with $3 a + 3 b + a b + {b}^{2}$
We can factor out the $3$'s and $b$'s like so:
$3 \left(a + b\right) + b \left(a + b\right)$
Then finally we can factor by $\left(a + b\right)$:
$\left(3 + b\right) \left(a + b\right)$