4 + n - 9 = 9 + 1 + 2n + 12
Cancel equal terms on both sides of the equation
4 + n = 1 + 2n + 12
Add the numbers
4 + n = 13+ 2n
Move variable to the left side and change it's sign
4 + n = -2n = 13
n - 2n = 13 - 4
Collect the like terms
- n = 13 - 4
n = -9
Change the signs on both sides of the equation
n = -9
