OOPS...
Part (a) of problem 2.5 reads:
"Find a primitive Pythagorean triples (a,b,c) with b = T5. Do the same for b = T6 and with b = T7."
The problem should read:
"Find a primitive Pythagorean triple (a,b,c) with b = 4T5. Do the same for b = 4T6 and b = 4T7."