$7m\:+8n\:-\:5m\:\:-10n$

$\left(a+3\right)\left(a-3\right)=a^2-9$

$\left(3b\right)^2$

$2\left|\left(x+1\right)\left(x+2\right)\right|$

$-\left[\left(-4\right).\left(-3\right)\right]$

$\frac{d}{dx}\left(y=\ln\left(t^2\right)-\arctan\left(\frac{t}{4}\right)\right)$

$4x^2-12x+2$