Question 451706
How did you get the answer, if you don't know how?  Do you mean the answer was given?
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It's a difference of 2 cubes.
{{{a^3 - b^3 = (a - b)*(a^2 + ab + b^2)}}}
If you remember one factor is a-b, you can divide it to find the other.
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PS  The sum of 2 cubes, a^3 + b^3 is
{{{(a + b)*(a^2 - ab + b^2)}}} similar to the difference above