$\left|\left(-4+9-1\right)\cdot\left(-1-2\right)\right|-\left|-\left(-5\right)+\left(-7\right)\right|\cdot4$

$\lim_{x\to-1}\left(\left(\frac{5x^4+5x^3+2x+2}{x+1}\right)\right)$

$\frac{dy}{dx}-1=-y^2+xy$

$\left(x-y\right)\left(dx-dy\right)=0$

$\:3xy\left(2xy-3y\right)$

$\ln\left(b^4\right)$

$\lim_{x\to\infty}\left(\frac{2x^2+7x}{5x^3+3}\right)$