$3\cdot3+5\cdot\left(7-3\right)$

$4\cdot\left(x-1\right)\cdot\left(x+2\right)\cdot\left(x+6\right)$

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

$\int\frac{e^{3x}-3}{e^{3x}+1}dx$

$x^2-6x-y+11=0$

$\frac { x - 4 } { 2 x - 4 }$

$\left\{-\left[\left(20+4\right).5-8\right].\left(11-18\right)\right\}$