Answer :

Yunuzaj
I would rearrange the equation and solve for 4m. So take the 6m across and the change its sign. Therefore 4m=8m-6m
4m=2m
For this you have to solve for m in the equation 6m+4=8m
Subtract 6m from both sides and you will have 4=2m 
Now you divide by 2 and you will get 2=m
now look at this equation 4m=?
Plug in the answer you got from before, which is 2. This means 4m=8