|
The first and last terms must be perfect squares. The square roots of these, when multiplied together and doubled, must equal the value of the middle term. eg: 4x2 - 24xy + 9y2 Square roots are 2x and 3y; product doubled is 24xy If this is all true, then you can write the answer in one step; Use the square roots, and the sign of the middle term, to make two identical factors. |
 Example: 4x2 - 24xy + 9y2 The first & last terms are squares of 2x and 3y The middle term is negative = (2x - 3y) (2x - 3y) = (2x - 3y)2 |