Help! Can someone please explain how to do this. I have my final in one hour.

Answer:
n= -3 and n= -6
Step-by-step explanation:
[tex]n^2 = -18 -9n[/tex]
We need to solve this equation to find the value of n.
Rearranging:
[tex]n^2 +9n +18 =0[/tex]
This is a quadratic equation and we can solve by using factorization method.
We need to make factors of 18n^2 such that their sum is equal to 9n.
So solving,
[tex]n^2 + 9n +18 =0\\n^2 + 6n + 3n +18 =0\\n(n+6) + 3(n+6)=0\\(n+3)(n+6) =0\\=> n+3 =0 \,\, and n+6 =0\\n= -3 \,\,and \,\,n=-6[/tex]