I was bored a couple minutes ago and decided to solve this thing...
Answer: x = 10.52, n = 123.60 (to two decimal places)
In the last step, before finding x, I just used the quadratic equation. To find n, I just plugged x back into both the given equations and voila, n was the same in both. So it works.
Solution attached below as jpeg. Note that my handwriting depreciates greatly the farther along I get into any math problem
