$\left(\left(m-n\right)-1\right)^2$

$5a+9b+3-2b-20a-13$

$\int\frac{x+12}{\left(x-6\right)^2\left(x+3\right)}dx$

$2\int\tan\left(x\right)\sec\left(x\right)dx$

$\frac{9yx^2}{3xy}$

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

$\int\frac{24x^2}{\sqrt{49-x^2}}dx$