$8a+2b$

$\left(4r+2x-y\right)^2-\left(3r-2x+5y\right)^2$

$\left(\frac{1}{\sin\left(x\right)}+\cot\left(x\right)\right)\cdot\left(\cos\left(x\right)-1\right)$

$f\left(x\right)=\frac{x}{4}-x$

$cos\left(\arccos\left(\frac{\sqrt{2}}{2}\right)+\arcsin\left(\frac{\sqrt{3}}{2}\right)\right)$

$x^5-9x^4+33x^3-61x^2+56x-20$

$\left(8x+5\right)\cdot\left(8x+5\right)\cdot\left(8x+5\right)$