$\lim_{x\to-1}\left(\frac{25-x^2}{x^2-4x-5}\right)$

$\int\left(-6x^{2}+\frac{3}{10}x\right)dx$

$\frac{\tan\:^2\left(x\right)}{\sec\:\left(x\right)}=\sec\:\left(x\right)-\cos\:\left(x\right)$

$\sqrt{\left(-6\right)}^2+1^2$

$n=3+2\left(n-1\right)$

$\int\frac{3r-1}{r^{2}-r}dr$

$7\left(-9x-6\right)+\left(-x^2+9x+8\right)$