What is f(x)=2x^2-8 ?

It has two answers that are: -2, 2

For the answer to the question above, since the triangle is isosceles, the two legs have equal length. The coordinates of two vertices are given
P(3,3)
Q(3,1)
Assuming that PQ and QR are the legs of equal length, the distance between Q and R must be the same as the distance between P and Q
d = √[(3-3)² + (3-1)²
d = 2
Therefore, the coordinates of P is
(5,1)