How do you factor x2+6xy+9y2?

1 Answer
May 20, 2015

You can factor this by grouping.

The coefficients of x2 and y2 are, respectively, 1 and 9, the product of which is 9, which, in turn, can be factored in (3)(3).

So, we can rewrite our function as

x2+3xy+9y2+3xy

and factor it by two groups of two terms each:

x(x+3y)+3y(3y+x)

We can see that the parenthesis of each term are exactly the same, so we can use them as the common multiple of the whole equation that are multipling the rest:

(x+3y)(x+3y)

Done!