How do you factor x^2+3xy+2y^2?

1 Answer
Mar 24, 2015

Remember that for the general case
(x+ay) * (x+by) = (x^2 + (a+b)xy + (ab)y^2)
which is a result with the same form as the given expression

provided we can find two values for a and b such that
a+b = 3 and
ab = 2

The obvious pair is (1,2)
so
x^2+3xy+2y^2 = (x+y)(x+2y)