Answer:
x = 9 or x = -21
Step-by-step explanation:
Solve for x over the real numbers:
x^2 + 12 x - 189 = 0
The left hand side factors into a product with two terms:
(x - 9) (x + 21) = 0
Split into two equations:
x - 9 = 0 or x + 21 = 0
Add 9 to both sides:
x = 9 or x + 21 = 0
Subtract 21 from both sides:
Answer: x = 9 or x = -21
