2014-06-23T20:09:48+08:00

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A trinomial that is the square of a binomial is called a trinomial square. Trinomials that are perfect squares factor into either the square of a sum or the square of the difference.
Example: x^2-6x+9
= x^2 - 3x -3x + 9
= x(x-3) - 3(x-3)
= (x-3) (x-3)
2014-06-23T20:12:27+08:00

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(x + y)² =(x)² + 2(x)(y) + (y)²

therefore, if a trinomial is of the form (x)² + 2(x)(y) + (y)², it can be factored into the square of a binomial.

another examples:
1. (x + 2y + 1)²=x² + 4y² + 1 +4xy +2x + 4y
2. (2x + 3y + 2z)²=4x² + 9y² + 4z² +12xy + 8xz +12yz