SOLUTION: How do I factor 8r cubed - 64s cubed

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: How do I factor 8r cubed - 64s cubed      Log On


   

Question 114614:
How do I factor 8r cubed - 64s cubed
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
8R^3-64S^3 EXTRACT 8.
8(R^3-8S^3) NOW YOU HAVE 2 DIFFERENT CUBES.
8[(R)^3-(2S)^3]
8[(R-2S)(R^2+2RS+4S^2)] ANSWER.
PROOF:
R^2+2RS+4S^2
R-2S
---------------------------
R^3+2R^2S+4RS^2-2R^2S-4RS^2-8S^3
(R^3-8S^3)
NOW MULTIPLY THIS EQUATION BY 8:
8(R^3-8S^3)
8R^3-64S^3