n² = -35 - 12n
Add 12n and 35 to both sides
n² + 12n + 35 = 0
Find the factors of 35 that add or subtract to positive 12:
Factors of 35: 1, 5, 7, 35
5 and 7 add up to 12
n² + 12n + 35 = 0
Instead of 12n, you can replace it with 7n + 5n because they add up to 12n
n² + 7n + 5n + 35
Factor the equation separately
n(n + 7) + 5(n + 7)
Now factor out the (n + 7)
(n + 7)(n + 5)
