Question

Which of the following is a solution of x^2 + 2x + 8?
A. 4 + i√7
B. −1 + i√7
C. 2 + i√7
D. −4 + i√7

Answer 1

x^2 + 2x + 8 = 0

(x + 1)^2 - 1 + 8 = 0

(x + 1)^2  =   -7

x + 1  = sqrt (-7)  = i sqrt7

x =  -1 + i sqrt7


Its B