$\lim_{x\to0}\left(\frac{sin\left(4x\right)-sin\left(8x\right)}{x}\right)$

$-3xy-2yx+6x^2+2y-x+y-4x-2x^2$

$\int_0^{\pi}\left(\frac{\left(1-tan^2x\right)}{sec^2x}\right)dx$

$14x^2y^2-28x^2+56$

$\int\left(\frac{x-4}{\left(x^2-8x+3\right)}\right)dx$

$\frac{\sqrt{x+1-2}}{x-3}$

$12x+5+3x-5$