SOLUTION: I'm not sure how to factor the difference of cubes, I always get confused. Please help: 64a(third power) + 27 and do you solve that problem the same way for this problem:

Question 60046: I'm not sure how to factor the difference of cubes, I always get confused. Please help:
64a(third power) + 27

and do you solve that problem the same way for this problem:
x(3rd power)y(3rd power) + 125?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
These problems are not the difference of cubes, they are the sum of cubes.
Formulas:
a^3+b^3=(a+b)(a^2-ab+b^2)
a^3-b^2=(a-b)(a^2+ab+b^2)
I'm not sure how to factor the difference of cubes, I always get confused. Please help:
64a(third power) + 27
=(4a+3)((4a)^2-(4a)(3)+3^2)
=(4a+3)(16a^2-12a+9)
-------------------
and do you solve that problem the same way for this problem:
x(3rd power)y(3rd power) + 125?
(xy+5)((xy)^2-(xy)(5) + 5^2)
=(xy+5)(x^y^2-5xy+25)
-----------
Cheers,
Stan H.

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