$11x\:+\:2\:-\:3y\:+\:4\:-\:y\:-\:8x$

$\lim_{x\to\infty}\left(\frac{\arctan\left(x^6\right)}{x^4}\right)$

$x^2-xy$

$\int_0^{\infty\:}\frac{e^{-t}}{e^t+e^{-t}}\:dt$

$\left(x-\frac{3}{5}\right)\left(x+\frac{5}{4}\right)$

$3\sin^2z=4\cos^2z$

$f\left(x\right)=3x^2+13x^2+2x-8$