Consider the equation:

Subtracting '4' from both the sides of the equation, we get as


Squaring on both the sides of the equation, we get


Subtracting '2' from both the sides of the equation, we get

x=14
Since, An extraneous solution is a solution that arises from the solving process that is not really a solution at all. But, in this equation x=14 is the solution of the given equation.
Hence, it is not an extraneous solution.
The answer is b. x=77, y=63
Answer is in the photo. I can only upload it to a file hosting service. link below!
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