$\cos\left(x\right)\left(\sin\left(x\right)-3cos\left(x\right)\right)$

$y=\frac{\sin\left(x\right)\cos\left(x\right)\tan^5\left(x\right)}{\sqrt{x}}$

$\int\frac{x}{\left(x+2\right)}dx$

$\lim_{x\to81}\left(\frac{\sqrt[4]{x}-3}{x-81}\right)$

$3\cdot0.1$

$2x^2-8x=-30$

$\frac{3x^2-3x}{2x^3-2x^2}$