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

$15x^2y-11x^2y+6x^2y+4x^2$

$f\left(x\right)=\frac{1}{2}\ln\left(\frac{1+x}{1-x}\right)$

$\:-log\left(\left(\left(\left(e\right)^{x+1}\right)^{-y-1}\right)\:\left(e^{\left(y\:\cdot\:x\right)}\:\right)\right)$

$-8\left(-4x\right)+-8\left(-6\right)$

$2x^2-13x+21=0$

$\int_e^{\infty}\left(x^{-20}lnx\right)dx$