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

$\left(x+\frac{1}{x}\right)^2=36$

$5x^3y\:-\:2x^3y$

$y-\left(2x\right)^2$

$\frac{1\cdot sen\left(x\right)-x\cdot cos\left(x\right)}{\left(2x\right)^2}$

$\lim_{x\to1}\left(\frac{6}{x^{1-x}}\right)$

$\left(-3x-4\right)\cdot\left(4x+5\right)$