Question

3/cube root (x+h) - 3/cube root (x)

Answer 1

Answer:

Problem is, you didn't FOIL it out all the way in the numerator:

(x+h−−−−−√3−x−−√3)((x+h)2/3+x2/3)=(x+h)+x+h−−−−−√3x2/3−(x+h)2/3x−−√3does not cancel−x

You're trying to use a difference of squares formula here, something like (a−b)(a+b) with a=x+h−−−−−√3 and b=x−−√3. But you don't want to square x−−√3, you want to cube it! So, instead, use a difference of cubes formula:

(a−b)(a2+ab+b2)=a3−b3