$\left(2x+1\right)\cdot\left(x+4\right)+\left(2x^3+5x^2+3x+1\right)$

$\frac{d^2}{dx^2}\left(\ln\left(x^4\right)\right)$

$2x+3\ge1$

$\frac { x ^ { 4 } - 1 } { x + x ^ { 2 } }$

$18-3\cdot4+2$

$\left(3x-5y-15\right)+\left(2x+y+16\right)$

$\int\frac{x}{\left(\sqrt{x^2+4}\right)^{\frac{5}{2}}}dx$