$\left|-2+1\right|-\left|5-7\right|-3\cdot\left(-1\right)+4\cdot\left|-4+1\cdot\left(3\right)\right|\left|-\left(2-3\right)\right|$

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

$\frac { x - 1 } { 3 } \leq 3$

$x-\sqrt{x-1}=1$

$\log3\left(27^x\right)=3x$

$\tan\left(30\right)+\cot\left(30\right)$

$\frac{sin\theta\:\:+sin^2\theta\:\:}{cos\theta\:+cos\theta\:\:sin\theta\:}=tan\theta\:$