$\lim_{x\to-1}\frac{4x+4}{x^3+x^2}$

$\frac{\sec\:\left(x\right)^2-1}{\sec\left(x\right)^2}$

$\frac{cosx+cotx}{cosx-cotx}$

$7a\:b+12b+a^2;\:a=-3;b=4$

$\lim_{x\to3}\:\:\frac{\left(x+1\right)}{\left(x-1\right)^2}$

$\int\left(x^2\cdot\left(2x^3-1\right)\right)dx$

$6-10f+f-10$