The correct answer is option 1 i.e. 5.
14+5326−73=11b+a3
On rationalization of the LHS part we get,
14+5326−73×14−5314−53
196−75364−1303−983+105 = 11b+a3
11469−2283=11b+a3
On squaring both sides we get,
469 - 2283 = b2 + 3a2 + 2ab3.
(19)2 + 3(-6)2 + 2 × 19 × (-6) = b2 + 3a2 + 2ab3.
on comparing we get,
a = -6 and b = 19,
(b−a) = (19−(−6) = 5.