Okay so what you want to do is since it is asking to combine like terms you would take the -m and add a positive m so: -m+m=0
So since we did it to one side we have to do it to the other and 3m plus another m would come out to a total of 4m. So now our equation should look like this: 6=4m+14
Now what you want to do is take away 14 from the right side to cancel it out, so, 14-14=0 Now that we've canceled that out we have to take 14 away from 6. Which 6-14 comes out to be -8. So now the problem should be -8=4m.
Alright now all that's left to do is to isolate the variable and find out what m is. So to do this you want to divide both sides by 4 so, -8÷4 and 4m÷4. Know -8 divided by 4 is -2, and for 4m divided by 4 the fours are going to cancel out leaving us left with the m.
So know all that's left is: -2=m
Therefore m = -2