Question

Pls help

Which of the following is a solution of x2 + 2x + 8? (1 point)

4 + i times the square root of 7

−1 + i times the square root of 7

2 + i times the square root of 7

−4 + i times the square root of 7

Answer 1

2+i times the square root of 7

Answer 2

B

Explanation:

Given

x² + 2x + 8 ( to find the solutions equate to zero )

x² + 2x + 8 = 0 ( subtract 8 from both sides )

x² + 2x = - 8

To solve we can use the method of completing the square

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

x² + 2(1)x + 1 = - 8 + 1

(x + 1)² = - 7 ( take the square root of both sides )

x + 1 = ±
`√(-7)` = ± i
`√(7)`

Subtract 1 from both sides )

x = - 1 ± i
`√(7)`