$\lim_{x\to\infty}-ln\left(\frac{\left(x^2\right)}{4}\right)$

$3x^2-8x-19$

$-20+2\cdot4-2\left(3-5\right)\cdot\left(2-3\right)-2\cdot\:\left[\:4+5\left(4-2\right)-3\right]$

$x^2\cdot dx+x\cdot y\cdot dy$

$6x^2+11x=9x^2+20x$

$\frac{x^3+3x^2+2x}{x+2}$

$80\:\frac{1}{2}\:-\:40\:\frac{1}{4}$