$81-9y^2$

$12-8x+2^2$

$\lim_{x\to0}\left(\frac{\tan\left(e^x-e^x+1\right)}{\left(e^x-1\right)^3}\right)$

$86+95+96.5+99.3+99.8$

$x^3-3x-13x+15$

$\left(\sin\left(x\right)+\cos\left(x\right)\right)^2\:+\:\left(sin\left(x\right)-\cos\left(x\right)\right)^2$

$\frac{csc^4\left(\theta\right)}{cot\left(\theta\right)sec^2\left(\theta\right)}$