for problem 6, you will want to subtract both sides by 5.
n^2 + 7n + 10 = 0
then factor:
(n + 5) (n + 2) = 0
n+ 5 = 0, n +2 = 0
n = -5, n = -2
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for problem 7, add - 12 and - 6 together
n^2 + 3n - 18
(you can put = 0 next to the equation since that can make it easier to solve, I guess)
n^2 + 3n - 18 = 0
then factor:
(n + 6) (n - 3) = 0
n + 6 = 0, n - 3 = 0
n = -6, n = 3
