$7-\left(-3\right)+\left(-8\right):\left(-8\right)-3-\left(-1\right)$

$\:-30+8-\left(-5\right)+1-5-\left(-3\right)+\left(-7\right)\:$

$16x-7\le-71$

$\lim_{x\to0}\left(\frac{2\:sen\:\left(\pi x\right)\:+\:\left(x^2\:-\:1\right)}{\left(1-x\right)^2}\right)$

$48x^2+52xy-30y^2$

$-\left(-2\right)+3x\left(-45\right)+35:\left(-5\right)$

$x^2+7x+6$