$\frac{1}{2}x^4+2x^3-\frac{2}{3}+\left(x-3\right).\left(\frac{1}{4}x^4+\frac{2}{3}x-x^5\right)$

$\frac{\left(secx-cosx\right)}{1+cosx}$

$abx^3-abx^3$

$\int\frac{\left(3\sqrt{x}-2x^4\right)}{\sqrt[7]{x}}dx$

$\int_0^{\pi}\left(7xcosx\right)dx$

$144x^8-60x^4y^2+16y^4$

$8=u$