Answer:
x = 1 ±√89
The correct option is C.
Step-by-step explanation:
To solve the equation; (x + 7(x-9) = 25, we will follow the steps below;
First, we will open the bracket
x² - 9x + 7x - 63 = 25
x² - 2x - 63 = 25
Add 63 to both-side of the equation
x² - 2x -63 + 63 = 25 + 63
x² - 2x = 88
We can now proceed to solve using the completing the square method.
Add the square of (-1) to both-side of the equation
x² - 2x + (-1)²= 88 + (-1)²
Factorize the left-hand side of the equation and simplify the right-hand side of the equation
(x - 1)² = 88 + 1
(x - 1)² = 89
Take the square root of both-side of the equation
√(x - 1)² = ±√89
x - 1 =±√89
Add 1 to both-side of the equation
x - 1+1 = 1 ±√89
x = 1 ±√89
