$\left(k+1\right)^2$

$9x^{-7}-6x^{-8}$

$10-\left(-7+5\right)$

$-5a^2b^2\left(3b-5b+16\right)$

$\lim_{x\to\infty}e^{-x^2}\ln\left(x\right)$

$\frac{x+6}{2}\le\frac{5-x}{4}$

$-\left(-23\right)+\left(-67\right)+\left|-14-\left(-22+12\right)-\left(-11\right)\right|-\left(-2\right)$