$1-4a^{3}b+3ab^{2}-8a^{3}b+6ab^{2}$

$\frac{cos^2x}{1-\sin x}-1=\sin x$

$2x-1<3x+8$

$\left(1-\sin^2\left(t\right)+\cos^2\left(t\right)\right)^2+4\sin^2\left(t\right)\cos^2\left(t\right)=4\cos^2\left(t\right)$

$36x^2-24xy+4y^2\:+\:3x^2+48y^2$

$\int\frac{x-4}{\sqrt{x}-2}dx$

$\left(6-k\right)^2$