SOLUTION: Expanding Brackets when cubed eg (x - 5)3 Answer given is xcubed -15xsquared + 75x -125 How do I work this? I can do two brackets but having trouble with the three brackets. Thank

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Expanding Brackets when cubed eg (x - 5)3 Answer given is xcubed -15xsquared + 75x -125 How do I work this? I can do two brackets but having trouble with the three brackets. Thank      Log On


   

Question 135417: Expanding Brackets when cubed eg
(x - 5)3 Answer given is xcubed -15xsquared + 75x -125 How do I work this? I can do two brackets but having trouble with the three brackets. Thanks
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Expand:
%28x-5%29%5E3 Rewrite this as:
%28x-5%29%28x-5%29%28x-5%29 Now multiply the first two factors using the FOIL method.
%28x-5%29%28x-5%29+=+x%5E2-5x-5x%2B25 = x%5E2-10x%2B25 now multiply this by the third factor.
%28x-5%29%28x%5E2-10x%2B25%29+=+x%5E3-10x%5E2%2B25x-5x%5E2%2B50x-125 Simplify to get:
x%5E3-15x%5E2%2B75x-125