$2t^2-3ut-4t+6u$

$x+10x$

$\lim_{x\to2}\left(x^3+5x^2-4x+1\right)$

$19xz^3+2xz^2-xz^3-11xz^2$

$\left(8a^3-4b^2\right)^2$

$\int\:\cot\:\left(-\frac{9}{2}x\right)dx$

$\left(\frac{2}{3}x^{\frac{-1}{2}}y^{\frac{3}{4}}-\frac{3}{4}x^{\frac{-3}{2}}y^{\frac{-1}{4}}\right)^2$