Let a and b are two positive real numbers such that a2 + b = 2, then the maximum value of term independent of x in the expansion of ax16+bx−139is ______

Tr+1=9Craa−rbrx3−r2So, for term independent of x, r = 3.∴Term independent of x=9C3a6b3Now using  A.M ≥ G.M. 3a23+3b36≥a6b33616⇒a6b3≤1So, maximum value of term independent of x is 9C3=84