$-\left(a+b\right)+\left[-3a+b-\left\{-2a+b-\left(a-b\right)\right\}+2a\right]$

$8+24x+42y+16+48x+32+96x$

$\frac{1}{\frac{\cos\left(x\right)}{\frac{\sin^2\left(x\right)+\cos^2\left(x\right)}{\cos\left(x\right)\sin\left(x\right)}}}$

$3\sqrt{5}+10\sqrt{5}$

$\sin^2b\cdot\left(\cot^2b+1\right)=1$

$2x-1<7$

$y-2^2$