You have the points:
(3, -6)
(-1, 1)
To find the distance between two point knowing the coordinates (x,y) you can use the next formula:
Then:
x1 = 3 y1 = -6
x2 = -1 y2 = 1
To simplify you can factorize the number under the root to know if the number can have a part that has a sqare root, as follow:
As you can see 65 can be writen as (5*13) and as none of those numbers have a perfect square root (whole number) the final answer is: