If the polynomials are to be added the result is:
-6x²+3xY+6Y² which factorises:
If the polynomials are to be multiplied the result is:
The two tables below help to calculate the coefficients. The top table deals with the product of the first two polynomials, and the other table with the product of this product and the third polynomial.
The column headers show which terms the coefficients belong to.