$x^2+12x-7\:=0$

$\lim_{x\to0}\left(\frac{\sin\left(x\right)-\sin\left(a\right)}{x-a}\right)$

$\lim_{x\to0}\frac{3^x-4^x}{x}$

$6y''+y'-y=0$

$\int_2^4\left(\frac{x^2-7x+10}{x-2}\right)dx$

$\int\sin^2\left(2x\right)\cdot\cos\left(2x\right)dx$

$\frac{d}{dx}\left(15^{-x}\right)$