[tex]9 = - 3 + n + 2n[/tex]
now let's flip this equation to make things easier
[tex] - 3 + n + 2n = 9[/tex]
now move -3 to the other side
when we move -3 to the other side it turns into positive 3
[tex]n + 2n = 9 + 3[/tex]
now add the values on both sides
n + 2n will be equal to 3n and 9 + 3 will be equal to 12
[tex]3n = 12[/tex]
now move 3 to the other side
the multiplication sign that binded 3 and n together will change into division when moved to the other side
[tex]n = \frac{12}{3} [/tex]
when we divide 12 and 3 we will get 4
[tex]n = 4[/tex]
so final answer is 4
hope that helps !
