Question

How do I even do this...

Answer 1

x = 2 ±
`√(15)`

Explanation:

x² - 4x - 11 = 0 ( add 11 to both sides )

x² - 4x = 11

to complete the square

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

x² + 2(- 2)x + 4 = 11 + 4

(x - 2)² = 15 ( take square root of both sides )

x - 2 = ±
`√(15)` ( add 2 to both sides )

x = 2 ±
`√(15)`