$\left(12a+7\right)-\left(3a-12\right)-\left(4a+6\right)$

$\lim_{x\to-\infty}\left(-1-xe^x+e^x\right)$

$m^2+2m^2-7m^2$

$62.26x^2y^6-13x^6y^2+169x^2y^2$

$\int sen\left(mx\right)cos\left(nx\right)dx$

$\left(1+\cos\left(x\right)\right)\left(\sec\left(x\right)-1\right)=\sin\left(x\right)\tan\left(x\right)$

$\int\frac{\left(x\right)}{\sqrt{x^2-8}}dx$