Tr+1=9Cr(x2/3)9−r(2x−2/5)r=9Cr(21)r(r)(632r52r)
for coefficient of x2/3, put 6−32r−52r=32 ⇒r=5 ∴ Coefficient of x2/3 is =9C5(51)5 For coefficient of x−2/5, put 6−32r−52r=−52 ⇒r=6 Coefficient of x−2/5 is 9C6(21)6 Sum =9C5(21)5+9C6(21)6=421