$\left(\frac{3}{7}x+7y^2\right)\left(\frac{3}{7}x-y^2\right)$

$x^4-2^2$

$\int\frac{x^2}{x^4-20x^2-125}dx$

$\int\left(x^2+3x+4\right)^3\left(2x+3\right)dx$

$\lim_{b\to2}\frac{1}{\left(b-2\right)^2}$

$\tan\left(x\right)=\frac{-\frac{1}{5}}{\cos\left(x\right)}$

$2x^7+3x^7-2y^2-5y^2$