For this case we have the following equation:

From here, we must clear the value of x.
For this, we follow the following steps:
1) We raise both members of the equation to the square:

2) We pass the number 1 subtracting:

3) We pass number 8 dividing :

We observe that the given equation can be evaluated for the solution obtained.
Therefore, the solution is valid.
Answer:
C) x = 3, solution is not extraneous