Therefore, the equation listed is X+X+3X+9X=28.
The combination of similar items can get 14X=28.
When the coefficient is normalized to 1, X=2.
Then X=2 is brought into 2+2+6+ 18=28 in the formula.
Thus, chicken is 2, duck is 2, goose is 6, and dog is 18.
This goose weighs 6 kilograms.