$+\left(+2\right)-\left(-7-3\right)+12$

$18p-36\:$

$\left(mn-8a\right)^2$

$\int_{\frac{\pi}{6}}^{\frac{\pi}{3}}3\sec^4\theta\:\:d\theta\:$

$\tan\left(a\right)\cdot\cot\left(a\right)\cdot\sin^2\left(a\right)$

$\frac{\sin\left(x\right)^2}{\cos\left(x\right)^2}+\frac{\cos\left(x\right)^2}{\sin\left(x\right)^2}+2$

$4x\:+\:5x\:=\:45$