$\lim_{x\to+3}\left(\frac{1}{3-x}-\frac{4x}{9-x^2}\right)$

$\left(y^2\right)\left(y^4\right)\left(y^8\right)\left(y^{16}\right)$

$\sqrt[3]{b^8}$

$12a^4-75b^4$

$\lim_{x\to4}\left(\frac{x^2-6-\sqrt{x+6}}{\sqrt{x+1}-2}\right)$

$\left(-8\right).\left(-9\right),1,2,5$

$\left(-8a^3+5a\right)\left(-8a^3+3a^2\right)$