$-13-\left(+12\left(+15-\left(\left(5-9\right)-7\right)-\left(-\left(9-7\right)-2\right)\right)\right)$

$\int_1^{\infty}\left(\frac{x+1}{x\left(x^2+1\right)}\right)dx$

$\int\:\left(x+2\right)sen\left(x^2+4x+4\right)dx$

$81a^2b^4+54a^6b^3+9a^4b^2$

$25x^2+50y^2+5x-25=0$

$\left(4x+xy^2\right)\frac{dx}{dy}+x^2y=y$

$\lim_{x\to0}\left(-6+5n\right)^5$