$\lim_{x\to1}\left(\frac{ln\left(1-x\right)-tan\left(7\right)}{x^2}\right)$

$\frac{x^4+x^2+2}{x-2}$

$\left(2a^{3}y^{2}z-5ay^{3}z^{2}\right)\left(2a^{3}y^{2}z+\san^{3}z^{2}\right)$

$4a^2+12a+8=-2$

$\int_1^3\left(-x^2-4x\right)-\left(-x^2+4x\right)dx$

$125\cdot5$

$b^2+2b-3$