Solve for a:
a^2 = 4 a+117
Subtract 4 a+117 from both sides:
a^2-4 a-117 = 0
The left hand side factors into a product with two terms:
(a-13) (a+9) = 0
Split into two equations:
a-13 = 0 or a+9 = 0
Add 13 to both sides:
a = 13 or a+9 = 0
Subtract 9 from both sides:
Answer: |
| a = 13 or a = -9
