$\frac{\left(-540\right)}{\left(-12\right)}$

$4x^2y+20xy^2$

$-\left(9-4+5\right)-\left(-3+11\right)$

$16m^2\left(x+y\right)-40m\left(x+y\right)+25$

$\frac{1}{\sin\left(x\right)^2}-\frac{1}{\cos\left(x\right)^2}-\frac{\cos\left(x\right)^2}{\sin\left(x\right)^2}$

$1+\left(x+1\right)\cdot\left(x-1\right)$

$\lim_{x\to+\infty}\left(\frac{6x}{\ln\left(x\right)+3x}\right)$