Find the distance d(P1,P2) between the points P1 and P2

Question

P1=(-1,5);P2=(2,4)

d(P1,P2)=

Answer 1

P1(-1,5) P2(2,4).

D^2 = (2-(-1))^2 + (4-5)^2 = 10
D = 3.16.