$6x^2-4ax-9bx+6ab$

$\left(4^3\right)^2.4^2$

$a+\left(\left(-2a+b\right)-\left(-a+b-c\right)+a\right)$

$\left(3\right)^2e^{\left(3\right)}-2\left(3\right)e^{\left(3\right)}+2e^{\left(3\right)}$

$\frac{9x^2-3}{3\sqrt{x}-2}$

$0.25x^2-0.3xy+0.09y^2$

$\sqrt{x^4}\cdot y^6$