$-7\:.\:\left(-9\right)$

$\frac{\cos^2}{\sin^2+3\sin+2}=\frac{1-\sin}{\sin+2}$

$\frac{10x^4-8x^3+10x^2-6x}{-x+2-3}$

$\int-5x^3\left(-6x^4+6\right)^4dx$

$\left(x^2+1\right)\frac{dy}{dx}+2xy=x^3+x$

$\lim_{x\to0}\left(\frac{ln\left(x^2+10x\right)}{lnx}\right)$

$x\sqrt{2x}$