$\left(4m+6\right)\left(4m-9\right)$

$\frac{3x^3+2x-1}{x+2}$

$x^2-4y^2$

$\left(+12\right)-\left(-3\right)+\left(-1\right)$

$\left(5x-1\right)^2-\left(3x+1\right)^2$

$\frac{sin\left(x\right)}{1-cos\left(x\right)}=\frac{1}{sin\left(x\right)}+\frac{1}{tan\left(x\right)}$

$\lim_{x\to2}\left(\frac{x^4+3x^3\:-10x^2}{x^2-2x}\right)$