Answer:
when P(x,y) is reflected in y=x line then
P(x,y) = P(y,x)
A(2, -1)= A(-1, 2)
B(-2, -1) = B(-1, -2)
C(2, 1)= C(1, 2)
D(1,2)= D(2,1)
Step-by-step explanation:
Its A.........................................
The answer to your question is: D it has 3
take square root and subtract y2 from y1 and x2 from x1