Chapter A.5, Problem 39E

In Problems $39\text{-}42$, write each expression in the form $a{x}^p+b{x}^q$ or $a{x}^p+b{x}^q+c{x}^r$, where $a$, $b$, and $c$ are real numbers and $p$, $q$, and $r$ are integers. For example,

$\frac{2x^4-3x^2+1}{2x^3}=\frac{2x^4}{2x^3}-\frac{3x^2}{2x^3}+\frac{1}{2x^3}=x-\frac{3}{2}{x}^{-1}+\frac{1}{2}{x}^{-3}$

$\frac{7x^5-x^2}{4x^5}$