$\frac{2x^3}{3+4x^2}$

$18b^2+90b+100$

$\frac{3x+2y\ge\:6}{x-y+1\ge\:0}$

$16<2x-4$

$\int\left(-2\cdot x\cdot e^x\right)\cdot dx$

$\int\left(\frac{1}{\left(\sqrt{x}\right).\left(1-x^2\right)}\right)dx$

$\lim_{x\to0}\left(\frac{arctan\left(x\right)-sen\left(x\right)}{3x^3e^x}\right)$