Answer
$-\frac{5}{7}$
Work Step by Step
$\frac{5x}{x^3+5}=\frac{5}{x^2-7}$ cross multiply
$5x(x^2-7)=5(x^3+5)$ distributive property
$5x^3-35x=5x^3+25$ subtract $5x^3$ from each side
$5x^3-35x-5x^3=5x^3+25-5x^3$ combine like terms
$-35x=25$ divide both sides by -35
$-35x\div-35=25\div-35$ simplify
$x=-\frac{5}{7}$
