# How do you combine (b^3 + 2b^2 + 3b) + ( 4b^3 - 5b^2 + 4b)?

Regroup based on factors of $b$ with the same exponent values:
$= \left({b}^{3} + 4 {b}^{3}\right) + \left(2 {b}^{2} - 5 {b}^{2}\right) + \left(3 b + 4 b\right)$
$= 5 {b}^{3} - 3 {b}^{2} + 7 b$