Answer:
x = 6 ± 5
Explanation:
Given
x² - 12x = 39
Using the method of completing the square
add ( half the coefficient of the x- term)² to both sides
x² + 2(- 6)x + 36 = 39 + 36
(x - 6)² = 75 ( take the square root of both sides )
x - 6 = ±
= ± 5
( add 6 to both sides )
x = 6 ± 5
← solutions in exact form