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

$3x^2-18x+27$

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

$\left(2a-6\right)\left(a-\frac{1}{3}\right)$

$-7xy^3z^2+3x^2yz^3+7x^2yz^3-13xy^3z^2$

$36a^8b^{12}-9c^{10}$

$\frac{64}{1\:+\:tan\left(64^{\circ}\right)\:tan\left(43^{\circ}\right)}$