B= 3x²y + 3xy² + 6x² +6xy + 6y²+2
B =3xy(x + y) + 6xy + 6x² + 6y² + 2
B =6xy + 6xy + 6x² + 6y² + 2
B = 12xy + 6x² + 6y² + 2
B = 6x(2y + x) + 6y² + 2
B = 6xy + 12x + 6y² + 2
B = 6y(x + y) + 12x + 2
B = 12y + 12x + 2 = 12(x + y) + 2 = 12.2 + 2 = 24 + 2 = 26
Vậy B = 26 với x + y = 2