$\left(2x\right)\left(-2y+z\right)$

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

$0.4x^2-3.2+3.9x+1.3x^2-2$

$4\ln\left(\frac{e^{2x}}{e^{2x-1}}\right)$

$\sin\left(3x\right)-\frac{\sqrt{3}}{2}=0$

$\left(x+2\right)^2-\left(x-2\right)^2+\left(x+4\right)^2-x^2-16$

$9x^2+5x+2\:\:para\:x=-1$