$-69-\left(-75\right)$

$\left(a^3+7\right)\left(a^3-7\right)$

$y=\frac{4}{x^{-3}}$

$\lim_{x\to1}\left(\frac{\:\:-2\:x\sin\left(x\pi\right)}{\pi\:\left(x^2\:-1\right)}\right)$

$\int_0^1\left(\frac{1}{x^2+49}\right)dx$

$x^2y+xy^2x^2z+y^2z+2xyz$

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