Verified answer

sqaure both sides

x^2+ 16 = 25

x^2 = 9

x= +/- 3

hence C

the square root of x squared is simply x. Now if that square root symbol goes over the 16 too, then the square root of x^2+16 is x + or - 4, leaving you with x+4=5 and x-4 =5, so x=1 and 9. If the square root only goes over the x^2, then x+16=5, so x=-11.

√(x^2 + 16) = 5

square both sides

x^2 + 16 = 25

subtract 16

x^2 = 9

Take the square root of both sides.

|x| = 3

x = ±3

Check that both solutions are valid. They are. Sometimes squaring something can add extraneous solutions.

The answer is C

you extract the square root both sides: there are 2 solutions -3 and +3...! So C

(sqrt x^2+16=5)^2

x^2+16=25

x^2=-9

D +/- 3i