$\frac{2ax+4by}{3ay+6bx}$

$\lim_{x\to2}\left(\frac{4x^2-8x}{2x^2-4x}\right)$

$4a^2-7;a=-2$

$\ln\left(2x+1\right)+\ln\left(x-2\right)-2\ln\left(x\right)=0$

$\left(\:9xy^2\:+\:8x^2y\:\right)\:\left(\:9xy^2\:-\:8x^2y\:\right)$

$2m^4n^2.2mn^4$

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