We can plug those values into the equation, and if the answer is incorrect, we'll know if either one is extraneous.
√11 - 2(-7) = √(-7)^2 + 4(-7) + 4
√25 = √25
5 = 5
The first solution, -7, makes the equation true, and so it is not extraneous.
√11 - 2(1) = √(1)^2 + 4(1) + 4
√9 = √9
3 = 3
The second solution, 1, makes the equation true, and so it is also not extraneous.
The correct option is D, neither solution is extraneous.
