pythagorean theorem c2 = a2 + b2
x2 + (x + 1)2 = 52
x2 + x2 + 2x + 1 - 25 = 0
2x2 + 2x - 24 = 0
x2 + x -12 = 0
(x + 4) (x - 3) = 0
x = -4 or x = 3
x can't be negative.
One of the leg = 3
The other leg = 3 + 1 = 4
It's a 3-4-5 triangle. One of pythagorean triplets.