$\frac{25a^2-121}{5a-11}$

$\left(4a-9\right)x\left(16a^2+36a+81\right)$

$1-\frac{tan\left(x\right)cos\left(x\right)}{csc\left(x\right)}=cos^2\left(x\right)$

$4xy^2\left(3y-x\right)-2x^2\left(x-3y\right)^2$

$16-y^2$

$\lim_{x\to\infty}\frac{2x^2+5x-8}{x+3}-2x$

$a^3b^2-2a^3b$