Answer:
x ≈ - 3.9 , x ≈ 5.9
Explanation:
x² - 2x - 23 = 0 ( add 23 to both sides )
x² - 2x = 23
using the method of completing the square
add ( half the coefficient of the x- term)² to both sides
x² + 2(- 1)x + 1 = 23 + 1
(x - 1)² = 24 ( take square root of both sides )
x - 1 = ±
( add 1 to both sides )
x = 1 ±
then
x = 1 -
≈ - 3.9 ( to 1 dec. place )
x = 1 +
≈ 5.9 ( to 1 dec. place )