Question 807981
(2x+1) is the length of ladder which is the hypotenuse

2x is one leg
and x-1 is the other leg

(2x)^2+(x-1)^2= (2x+1)^2  

4x^2+x^2-2x+1=4x^2+4x+1

x^2-6x=0
x^2=6x

x=6 Or x=0
x cannot be 0

5,12,13