Answer: 5.29150262213
or just 5.29
Explanation:
The formula to find the distance between 2 points is

(The one and 2 next to the x and y's mean to square it)
A is 0, -5 and B is 2, 1.
(0 squared - 5) 2 = 25, and (2 squared - 1 squared) = 3
25+3 = 28, 28 squared is 5.29150262213.
:)
(Sorry if I am wrong)