$\frac{2}{10}xy+\frac{1}{5}xy+\frac{3}{5}xy$

$\left(-3\right)\cdot\left(-1\right)+\left(-2\right)\cdot\left(-2\right)$

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

$\int x^2\cdot\cos\left(3x\right)$

$8cos^2x=4+4cos2x$

$-9z^3\cdot3z^4$

$4\left(ad+bc\right)^2-9$