$\int_1^6\left(\frac{x}{x^2-b^2}\right)dx$

$\int x^3\left(a^2+x^2\right)dx$

$\left(m^{5}+3m^{2}-6-2m^{4}\right):\left(m+1\right)$

$\frac{tg^2a}{1-\cos^2a}-\frac{1}{\sec^2a}=1$

$64t^2-144$

$\int\frac{4v^2}{\left(16-v^2\right)^{\frac{5}{2}}}dx$

$2\:\left(x\:+\:6\right)\:+\:3x\:+\:4$