Hi, it is simple
Use the formula:
Let A = (5,4) and B = (-3,-1)
Where,
A = (xa, ya) and B = (xb , yb)
Then,
d(A, B) = √(xb -xa)^2 +(yb-ya)^2
Replacing it:
d(A, B) = √(-3-5)^2+(-1-4)^2
= √(-8)^2+(-5)^2
= √(64+25)
= √(89)
As the question does not specify the unit of measure.
d(A, B) = √(89) u.m
Unit of measure
Hope this helps!