Answer
$-\frac{2}{5}x^{4}$ + $x^{3}$ - $\frac{1}{8}x^{2}$
Work Step by Step
($\frac{1}{5}x^{4}$ + $\frac{1}{3}x^{3}$ + $\frac{3}{8}x^{2}$ + 6) + (-$\frac{3}{5}x^{4}$ + $\frac{2}{3}x^{3}$ - $\frac{1}{2}x^{2}$ - 6)
The like terms are $\frac{1}{5}x^{4}$ and -$\frac{3}{5}x^{4}$ (both containing $x^{4}$) , $\frac{1}{3}x^{3}$ and $\frac{2}{3}x^{3}$ (both containing $x^{3}$) , $\frac{3}{8}x^{2}$ and - $\frac{1}{2}x^{2}$ (both containing $x^{2}$) , 6 and -6 both are constants
We begin by grouping these pairs of like terms
= ($\frac{1}{5}x^{4}$ -$\frac{3}{5}x^{4}$) + ($\frac{1}{3}x^{3}$ +$\frac{2}{3}x^{3}$) + ($\frac{3}{8}x^{2}$ - $\frac{1}{2}x^{2}$ )+ (6 -6)
=$-\frac{2}{5}x^{4}$ + $x^{3}$ - $\frac{1}{8}x^{2}$