$\left(3-x\right)\left(\frac{7}{x^2}-6\right)$

$\int\frac{5x+7}{\left(x+2\right)^2}dx$

$\int\frac{\cos\left(u\right)}{u}du$

$1-\sen\theta\cdot\cos\theta\cdot\tan\theta=\cos^{2}\theta$

$\left(2a^2b-1\right)\left(2a^2b+3\right)$

$\left(u-1\right)^3$

$\left(2x-6\right)\left(6-8x\right).\left(3x^2-9x\right)\left(2x-2\right)$