He solve this equation: 0.2 - 2m = 2.1m + 2.5 - 1.8m

Step-by-step explanation:

First simplify it.  Combine like terms.

0.2 - 2m = 2.1m + 2.5 - 1.8m

0.2 - 2m = 0.3m + 2.5

Then isolate m.  Add 2m on both sides, then subtract 2.5 from both sides.

0.2 - 2m = 0.3m + 2.5

        0.2 = 2.3m + 2.5

       -2.3 = 2.3m

Now divide by 2.3 to find m.

       -2.3 = 2.3m

           -1 = m

And so m = -1.

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.

step-by-step explanation: