9 = -3 + n + 2n what does n equal ?

now let's flip this equation to make things easier

now move -3 to the other sidewhen we move -3 to the other side it turns into positive 3

now add the values on both sidesn + 2n will be equal to 3n and 9 + 3 will be equal to 12

now move 3 to the other sidethe multiplication sign that binded 3 and n together will change into division when moved to the other side

when we divide 12 and 3 we will get 4

so final answer is 4hope that helps !