$60-\left(8-5\right)^3+\left(-2\right).\left[\left(-2\right)^4+3.\left(2-7\right)\right]$

$2^{-3}+2^{-1}+2^0+2^1+2^2$

$\lim_{x\to0}\left(\frac{1}{\sin\left(x\right)}-\frac{1}{e^x}\right)$

$3xy-2x+2xy$

$7y^2-2y-5$

$\left(x^2+5\right)\left(x^2-15\right)$

$5-\left(3-10\right)$