$x^4+1-3\cdot x\cdot\left(x+1\right)\cdot\left(x-1\right)$

$x^2+9x=-8$

$\left(-3\right)\cdot\left(-6\right)-\left|\left(-4-\frac{10}{2}\right)-\left(-4\right)\right|$

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

$pq-qy+py-qy$

$\left(x+4\right)\left(x-4\right)+\left(5+x\right)\left(5-x\right)$

$5m-9n+2n$