$x^2-\:6x\:+\:y^2\:=\:7$

$x\:+\:2cm\:+\:x+12cm+2x\:+\:15cm\:+\:3x\:+20cm$

$\frac{x^2-2x-5}{x+1}$

$\int\left(4x-3\right)^5dx$

$\frac{\sin\left(\frac{x+y}{4}+\cos\left(\frac{x+y}{2}\right)\right)}{\cos\left(x+y-85\right)+\sin\left(x+y-120\right)}$

$216m^{12}+864m^8$

$\lim_{x\to3}\left(\frac{x^2-6x+9}{x^2-x-6}\right)$