$\frac{\left(2x+1\right)}{x+2}<1$

$n^4-81$

$-2^4:\left(-4\right)+\sqrt{25\cdot4}+\left(3\cdot3-5\right)^2$

$\frac{\cot\left(x\right)\sin\left(x\right)}{\cos\left(x\right)}=1$

$h\left(x\right)\:=\:\left(4\:x^{2\:}-\:3x\:+\:6\right)^2$

$\left(18x^2-y\right)^2$

$-3a^2b+7ab+7a^3b^2-8a^2b-5ab$