b: length of the longer leg. a = (b-7) , c = (b+1)
(b-7)2 + b2 = (b+1)2
b2 - 14b + 49 + b2 = b2 + 2b + 1
b2 - 16b + 48 = 0
(b - 4)(b - 12) = 0
b = 4 or b = 12 but b ≠ 4 since that would make a < 0.
a = 5 , b = 12 , c = 13. The hypotenuse is 13 nanometers.