Answer:
x = 1 + sqrt(89) or x = 1 - sqrt(89)
Step-by-step explanation:
Solve for x:
(x - 9) (x + 7) = 25
Expand out terms of the left hand side:
x^2 - 2 x - 63 = 25
Add 63 to both sides:
x^2 - 2 x = 88
Add 1 to both sides:
x^2 - 2 x + 1 = 89
Write the left hand side as a square:
(x - 1)^2 = 89
Take the square root of both sides:
x - 1 = sqrt(89) or x - 1 = -sqrt(89)
Add 1 to both sides:
x = 1 + sqrt(89) or x - 1 = -sqrt(89)
Add 1 to both sides:
Answer: x = 1 + sqrt(89) or x = 1 - sqrt(89)
