4n+3n=5n+10
7n= 5n+10.
Move 5n to the other side. Sign changes from +5n to -5n.
7n-5n= 5n-5n+10
2n= 10
divide by 2
2n/2= 10
Cross out 2 and 2, then divide by 2. Then becomes n= 5
Answer: n= 5