$\frac{x-4}{2\sqrt{x-4}}$

$\left(\frac{3}{4}c^2-5t\right)\left(\frac{3}{4}c^2+5t\right)$

$i^2+18i+49$

$\lim_{x\to0}\left(\frac{-\cos\left(x\right)}{3x^2}\right)$

$\sqrt[5]{89x^{15}}$

$\frac{d}{dx}\frac{2x+3}{x+12}$

$\frac{cos2\left(x\right)}{sin\left(x\right)}+sin\left(x\right)=\frac{cot\left(x\right)}{sec\left(x\right)}$