$\:9m\:+\:5mn\:$

$-8x^3+14x^2-16x-28$

$-9\:r\:-51$

$\left(1+2j\right)\left(2+7j\right)$

$\left(8+\left(-4\right)\right)+2\left|5-3\left(5-3\right)+\left(-4\right)\right|-\left(4+\left(-2\right)\right)$

$\left(x+2\right)\left|\left(x+2\right)^2-4x+\left(x-2\right)^2\right|-16$

$\frac{\left(\frac{8a-3b}{2c+1}\right)}{\left(\frac{2a}{bc}\right)};a=-2;b=1;c=-1$