
John R. answered 07/01/13
John R: Math, Science, and History Teacher
The sum of cubes states that a3 + b3 = (a + b)(a2 - ab + b2)
Using the sum of cubes, we can factor the numerator:
[(x + y)(x2 - xy + y2)]/(x - y)
Since there are no common factors of then numerator and denominator, the fraction cannot be reduced.
Note that if the numerator were x3 - y3, the factors would be (x - y)(x2 + xy +y2), which could be reduced.