$m\tan\left(50\right)=\tan\left(70\right)-\tan\left(20\right)$

$2x^2+8x-10=0$

$\lim_{x\to2}\left(\frac{5x^4-3x^2-68}{2x^5-3x^2+2x+8}\right)$

$8+x=7$

$\frac{d^2}{dx^2}\left(x^3-3x^2y+2xy^2=12\right)$

$\:\:\frac{1-\sin\:^2\left(\theta\:\right)}{\cos\:\left(\theta\:\right)}$

$\int\frac{4x}{x-9}dx$