Question

Which of the following is a solution to the equation 0=x2+6x+4 ?

A. x=−3−√5
B. x=−3−√25
C. x=−6+√5
D. x=−6+√25

Answer 1

A

Explanation:

Given

x² + 6x + 4 = 0 ( subtract 4 from both sides )

x² + 6x = - 4

Solve using the method of completing the square

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

x² + 2(3)x + 9 = - 4 + 9, that is

(x + 3)² = 5 ( take the square root of both sides )

x + 3 = ±
`√(5)` ( subtract 3 from both sides )

x = - 3 ±
`√(5)` , thus

x = - 3 -
`√(5)` → A

x = - 3 +
`√(5)`