Question
Factorise:
(x - 3y)3 + (3y - 7z + (7z - x)3
Solution
We have
(x - 3y) + (3y - 7z) + (7z - x) = 0
∴ (x - 3y)3 + (3y - 7z)3 + (7z - x)3
= 3(x - 3y) (3y - 7z) (7z - x)
