12x-6x^2
2y-6xy^3
6x^2-3
3xy^2-6x

12x-6x^2 --> 6x (2-x)

2y-6xy^3 --> 2y (1-3xy^2)

6x^2-3 --> 3 (2x^2-1)

3xy^2-6x --> 3x (y^2-2)

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.