$3-\left(-2+11-\left(4-15-7\right)\right)-2+\left(-3-\left(5-26-1\right)+2\right)\:$

$2\left(7ab^5\right)^0$

$\left(-x-2\right)^2=\left(x+2\right)^2$

$28-\left[-21-\left(12-3\right)-7\right]$

$\left(6a-4b+8\right)^2$

$m^2+2m-5\:entre\:m-1$

$\lim_{x\to0}\left(\frac{ln\left(x+1\right)-a\cdot sen\left(x\right)+sen\left(3x\right)}{x^2}\right)$