allright so what you do is like this. you are trying to solve for M and since both questions are equal, we can try to isolate so M is on one side and the rest is on the other.
1. The Right Hand Side is easier to isolate since M doesn't have any coefficants (numbers that are multiplied 5n) So what you do is you add 2/5 to both sides to to get ride of the -2/5 on the right hand side and add to the left hand side, your equation is (1/5)m - (8/5)=m what you could so next is...
2. You divide (1/5) from the left side m to isolate m from the coefficant, but doing this is also like multiplying the recipricol (the opposite, numerator is denominator, denominator is numerator) so you could multiply all side by 5 or (5/1) do this to everything in all sides so your -(8/5) is multiplied by 5 (makes just -8), what your equation looks like is m-8=5m, at the end just subtract m from the left side to to isolate the number on the left side and the variable on the right side. you get -8=4m, divide by 4 to isolate m and then you get -2=m or M=-2.
Hope this helps, i write too much.