$\left(28.5\right)-\left(-5.9\right)$

$\frac{5}{3}n^2m^3+\frac{1}{2}n^3m^2+\left(-\frac{1}{3}n^2m^3\right)+2n^3m^2$

$a^2+ab+7a^2+8ab-3ab-6a^2+11a^2$

$-71a-84b+50a+84b-45a+18a$

$\left(8b-6\right)\left(8b-4\right)$

$\log\left(2x-3\right)+\log\left(x+2\right)=1$

$5\left(2y^2+4y+2\right)$