Then (3/ 1+ (open 3 times) root 1) n = 1024.

Then 4 n = 1024

Then n=5

The general formula of binomial expansion is C(5, r) (3/x (1/2)) (5-r) (-x (1/3)) R.

=c(5,r)3^(5-r)x^(-(5-r)/2)(-x^( 1/3))^r

When r=3, the constant term is c (5.3) 3 (5-3) (-1) =-10× 9 =-90.