(5b^2 - 14ab) / (25b^2 - 196a^2)=b(5b- 14a) / ((5b- 14a)(5b+14a)) = b/(5b+14a)
√8/(5√8-14√2)=2√2/(10√2-14√2)=2√2/(-4√2)=-1/2
(5b^2 - 14ab) / (25b^2 - 196a^2)=b(5b- 14a) / ((5b- 14a)(5b+14a)) = b/(5b+14a)
√8/(5√8-14√2)=2√2/(10√2-14√2)=2√2/(-4√2)=-1/2