Solve the equation. Identify any extraneous solutions. √a=-2

A.4 is a solution of the original equation.
B.4 is a solution of the original equation. -4 is an extraneous solution*****
C.-4 is a solution of the original equation. -4 is an extraneous solution
D.No solution

I messed up on these before, can someone walk me through the steps?

2 answers

√a means the positive square root of a
√4 = 2, not ±2
Just because (-2)^2 = 4 does not make -2 equal to √4

So, as written, the equation has no solution, because √4 = 2, not -2
Ohhh... Now I see it.
Thanks! :)