$-x^2-3x-2$

$a^2-8a-12=0$

$\frac{24x^3y^2}{18xy^3}=\frac{4x^2}{3y}$

$-1^0$

$\left(-3m+\frac{6}{5}n\right)\left(8m-\frac{3}{8}n\right)$

$32.20+34.93$

$-\left[\left(-16\right)-\left(-5\right)\right]-\left\{-\left(-18\right)-\left(-8\right)-\left[\left(-19\right)-\left(-9\right)\right]-\left(-2\right)\right\}$