Q.

(x3+1x)5=

1 x5243+5x381+10x27+109x+53x3+1x5  
2 x5420+5x42+3x381+10x27+5x+2x4  
3 2x5243+4x43+3x381+10x9+109x+53x3  
4 None of these  

Ans.

(1)

We have, (x3+1x)5

=C05(x3)5+C15(x3)4(1x)+C25(x3)3(1x)2+C35(x3)2(1x)3+C45(x3)(1x)4+C55(1x)5

=x5243+5x381+10x27+109x+53x3+1x5