$\int-\frac{6x}{e^{2x}}dx$

$\lim_{x\to0}\cos\left(\frac{\pi}{x}\right)$

$\int xe^{\frac{\left(-x+1\right)}{12}}dx$

$2+\left(+1\right)\:-\left(-4\right)$

$4x^2-8x-1=0$

$\frac{d}{dx}-4y^2-9=0$

$tan\left(x\right)\left(cot\left(x\right)-cos\left(x\right)\right)=1-sin\left(x\right)$