$2a-\left(-3x+2\left(-a+3x-2\left(-a+b-2+a\right)\right)\right)$

$\lim_{x\to\infty}\left(\frac{x+a}{x+b}\right)^x$

$5\cdot5\cdot5\cdot3\cdot3$

$10b-3ab^2$

$m^{-28}\cdot m^{-1}\cdot m^{85}$

$\left(-4.5\right)-\left(0.5\right)-\left(5.5\right)-\left(10.5\right)-\left(15.5\right)+\left(6.5\right)+\left(2.5\right)+\left(4.5\right)+\left(6.5\right)+\left(7.5\right)$

$\left(6f^2-d^2h^3\right)\left(6f^2-5\right)$