$\lim_{x\to0}\left(\frac{xtan\left(x\right)-xsin\left(x\right)}{x^2sin\left(x\right)tan\left(x\right)}\right)$

$\left(-2x-3\right)\left(2x+3\right)\ge0$

$16\:-\:4\:x^2$

$\left(\frac{t+3}{-1+3}\right)\cdot\left(\frac{t-0}{-1-0}\right)\cdot\left(\frac{t-2}{-1-2}\right)$

$5\left(3x+20\right)$

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

$\left(-7\right)\left(4\right)\:+\:8\::\:\left(-2\right)\:-\:4\:+\:6:2$