Hi there! The answer is B. -7 or 7
The angles in a quadrilateral always add up to 360°. Therefore the angle of P is

So the angle of P is 49° and equals x^2. Therefore we get the following equation

Take the square root of both sides

OR

Since the angle must be positive, the value can as well be -7 as 7 (because the square of both of these numbers is 49°). Hence, the answer is B.