$\csc\left(x\right)^2\cdot\tan\left(x\right)^2=\csc\left(x\right)^2$

$\lim_{x\to3}\left(\frac{x^2-x+12}{x+3}\right)$

$3\left(-4\right)\left(-3\right)-4\left(4\right)+2\left(-2\right)$

$x^2+8x=3$

$\frac{25xy^2}{125x^5y^7}$

$\lim_{x\to7}\left(\frac{x}{x^2-49}\right)$

$\frac{8x^4+4x^2-1}{x^2-x-2}$