Note that 49b^2 - 256 = 0 is the difference of two squares. Thus, 49b^2 - 256 = 0 can be re-written as
(7b)^2 - 16^2 = 0, which factors into (7b+16)(7b-16)=0.
Solving for b: 7b+16=0 becomes b = -16/7, and
7b-16=0 becomes b = 16/7.
As expected, this 2nd order equation has 2 solutions.
