Factoring the Sum or Difference of Cubes - Problem 1 4,357 views
Factoring trinomials. Now for this particular problem we are factoring xÂ³ minus 8 which is the difference of cubes? If you think about it 8 is actually just 2Â³. So we need to go to our formula.
We have a formula for difference of cubes, aÂ³ minus bÂ³ is a minus b, the first sign is the same. 8Â² plus ab, the second sign is the opposite and then plus bÂ², the last sign is always positive.
So from here we just want to plug in the corresponding a and b. So looking at this we have aÂ³, xÂ³, so a is just going to be x, a is 2Â³. So b is just going to be 2, and then plugging in the corresponding values. So this is just going to be equal replacing a with x and b with 2.
X minus 2, xÂ² plus 2x plus 2Â² or 4. Using our formula our difference of cubes to factor xÂ³ minus 8.