$\lim_{x\to-\infty}\left(x^2-x^3+6x^5-x^7\right)$

$\left(a^9x^5+b^3\right)\left(a^9x^5+7b^3\right)$

$3x^2=9x$

$\int x^3\left(u\right)^2du$

$-\left|2\right|=-8$

$\frac{1+\sin\left(a\right)}{\cos\left(a\right)}=\frac{\cos\left(a\right)}{1-\sin\left(b\right)}$

$\int\sqrt{2x^{3}+3}\left(x^{2}\right)dx$