Question

none

Answer 1

To use Kathy's method, you would break -12x down into -6x - 6x, giving x^2 - 6x - 6x + 36. You would then take x out as a common denominator in the first group and 6 as a common denominator in the second group. x(x - 6) - 6(x - 6). It can now be grouped as (x - 6)(x - 6), or (x - 6)^2

Tom is correct. This is a special pattern known as a perfect square trinomial. That means that the first and third terms are both perfect squares. Factors of 36 are 6,6 and -6, -6. Since the middle term is negative, the negative factors of 36 must be used. So the expression can be written as (x - 6)(x - 6) or (x - 6)^2.

The two methods give the same result, but recognising the pattern makes it quicker and easier