$20-2^2-1^3\cdot3$

$2xy^2z^3-\:18x^3z$

$\left(x-1\right)dy+x^2\sqrt{y}dx=0$

$\frac{7}{8}m+\frac{9}{10}-2m-\frac{3}{5}\:$

$12x^2+3x-3=0$

$\sin a\cdot\cos\left(b-a\right)+\cos a\cdot\sin\left(b-a\right)=\sin b$

$\lim_{x\to\infty}\left(\sqrt{\left(4x^2-6x\right)-2x-1}\right)$