Answer
$-\frac{2}{5}x^{4}$ + $x^{3}$ + $\frac{3}{8}x^{2}$
Work Step by Step
($\frac{2}{5}x^{4}$ + $\frac{2}{3}x^{3}$ + $\frac{5}{8}x^{2}$ + 7) + (-$\frac{4}{5}x^{4}$ + $\frac{1}{3}x^{3}$ - $\frac{1}{4}x^{2}$ - 7)
The like terms are $\frac{2}{5}x^{4}$ and -$\frac{4}{5}x^{4}$ (both containing $x^{4}$) , $\frac{2}{3}x^{3}$ and $\frac{1}{3}x^{3}$ (both containing $x^{3}$) , $\frac{5}{8}x^{2}$ and - $\frac{1}{4}x^{2}$ (both containing $x^{2}$) , 7 and -7 both are constants
We begin by grouping these pairs of like terms
= ($\frac{2}{5}x^{4}$ -$\frac{4}{5}x^{4}$) + ($\frac{2}{3}x^{3}$ +$\frac{1}{3}x^{3}$) + ($\frac{5}{8}x^{2}$ - $\frac{1}{4}x^{2}$ )+ (7 - 7)
=$-\frac{2}{5}x^{4}$ + $x^{3}$ + $\frac{3}{8}x^{2}$
