Answer
$= \frac{26}{15x^{3}}$
Work Step by Step
1) Multiply a fraction with the other denominator to obtain a common denominator between the two fractions. In this case, we multiply the first fraction by $3/3$ and the second fraction by $5/5$ to obtain a common denominator of $15x^{3}$
2) Add the fractions
$= \frac{-8}{5x^{3}} + \frac{10}{3x^{3}}$
$= \frac{-8(3)}{15x^{3}} + \frac{10(5)}{15x^{3}}$
$= \frac{-24+50}{15x^{3}}$
$= \frac{26}{15x^{3}}$
