Question

Solve the equation by completing the square x^2-18x=19

Answer 1

x = - 1 , x = 19

Explanation:

x² - 18x = 19

to complete the square

add ( half the coefficient of the x- term)² to both sides

x² + 2(- 9)x + 81 = 19 + 81

(x - 9)² = 100 ( take square root of both sides )

x - 9 = ±
`√(100)` = ± 10 ( add 9 to both sides )

x = 9 ± 10

then

x = 9 - 10 = - 1

x = 9 + 10 = 19