M = 4, 1. 5=5m+2m-23 2. 5=7m-23 3. 28=7m 4. m=4. The first step is just me rewriting the problem so that like terms are right by each other. On the left side I added the like terms, 5m and 2m. That equals 7m. Now, looking at the second step. To get rid of the -23 on the left side, we add 23 to it which cancels it out. We have to add 23 on the other side too. So, 5+23 is 28. This brings us to step 3. 7m divided by 7 is M. And 28 divided by 7 is 4. This leaves us with the answer m=4.