$\frac{x+1}{x-7}+\frac{x-1}{x+7}=\frac{x}{x^2-49}$

$\left(x^2-2\right)\left(x-1\right)\left(x^2-x+1\right)$

$\left(\left(a+b\right)^2+c\right)^2$

$100-12+5-11+12-13+8-11+4-15+6-13-9+8$

$-y\left(5x^3-7x^2y+xy^2+3y^3\right)$

$\frac{4x^3+7x+9}{2x-1}$

$\frac{\left(2x^{-1}\right)^{-3}}{\left(x^4y^{-1}\right)\left(x^{-1}y^2\right)}$