hello..

um i need some help to understand these questions please..

1. The length of the line joining A(2,-1) and B(5,y) is 5 unit. find y.

Please the only thing um stuck on is i dont get what 5 units means???

2.The point (h,k)lies on the line y=x+1 and is 5 units from the point (0,2). write down two equations connecting h and k..Again i dont understand the 5 unit..

PLease someone be niice enough and help me out..Much aprreciated it..Thankyou

Peace Out