2m+m-8=7 with shown work

Well since you are looking for m.

What you need to do is ...

First: add common factors in this problem 2m and m will get you 3m

The second step would be to have 3m alone so what you do is you add 8 to both sides cancelling out the 8 with m giving you:

3m = 15

Next you divid both sides by the number that is used by m in this case 3

Giving you m=5

2m+m-8=7

Combine 2m+m

3m-8=7 add 8

3m=15 divide by 3

M=5