The third term in the expansion  of (x2−1x3)n  is independent of x , when n  is equal to

Given  expansion   (x2−1x3)n  is We have general term in the expansion (x+a)n (∴  Tr+1= nCr xn−r (a)r  be the expansion of (x+a)n) T2+1= nC2(x2)n−2(−1x3)2  T2+1= nC2 (x2)n−2 (−1)2 (x−3)2 T3= nC2x2n−10 x2n−10 compare with x0  for finding r ⇒x2n−10=x0 will  contain x if 2n  −10 =0   ∵n=5 .