Originally Posted by

**Shakarri** For the cubic equation you are solving you should be able to factorize it so that it looks like

$\displaystyle (x-a)(x-b)(x-c)=0$

When you expand that you will see that -abc is the only term that is not multiplied by x or x^{2} or x^{3}

In your equation the only term not multiplied by x or x^{2} or x^{3} is 32 so -abc=32

If a, b and c are whole numbers (which is not always true but usually is for grade 9 maths) then in order for them to multiply together to give 32 they have to be the factors of 32. The only factors of 32 are: 1, -1, 2, -2, 4, -4, 8, -8, 16, -16, 32, -32 so if you try putting those into the equation you will find some of them which make the equation equal to zero. If you tried 4, for example, and found that putting that into the equation gave an answer of 0 then you know that 4 is a solution of the equation and (x-4) is a factor.