$-7>2x-6$

$\lim_{x\to\infty}\left(\frac{x^2}{e^{4x}-1-4x}\right)$

$4x^2-2xy+9y-18xy$

$\lim_{x\to-8\:}\sqrt{x^2-3x-4}$

$\int\frac{1}{\sqrt{36-81x^2}}dx$

$a^{\frac{4}{3}}+a^{\frac{1}{3}}$

$\lim_{x\to0}\left(\frac{e^{3x}-e^{-3x}}{2x}\right)$