(n - 4) - 3 = 3 - (2n + 3)
Remove the parenthesis, and combine like terms
n - 4 - 3 = 3 - 2n + 3
n - 7 = 3 + 3 - 2n
n - 7 = -2n + 6
add 2n to both sides and 7 to both sides to isolate the n
n - 7 (+7) = - 2n + 6 (+7)
n = -2n + 13
n (+2n) = -2n (+2n) + 13
3n = 13
isolate the n, divide 3 from both sides
3n/3 = 13/3
n = 13/3, or 4.33 rounded
hope this helps
