SOLUTION: Multiply. (4x-5)(x^2-4x+8) I want to check and see if I did it right. If I didn't do it right please help. my answer is 4x^3-11x^5-20

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Multiply. (4x-5)(x^2-4x+8) I want to check and see if I did it right. If I didn't do it right please help. my answer is 4x^3-11x^5-20       Log On


   

Question 319199: Multiply.
(4x-5)(x^2-4x+8)
I want to check and see if I did it right. If I didn't do it right please help.
my answer is 4x^3-11x^5-20

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
%284x-5%29%28x%5E2-4x%2B8%29 Start with the given expression.


4x%28x%5E2-4x%2B8%29-5%28x%5E2-4x%2B8%29 Expand.


Distribute.


4x%5E3-16x%5E2%2B32x-5x%5E2%2B20x-40 Multiply.


4x%5E3-21x%5E2%2B52x-40 Now combine like terms.


So %284x-5%29%28x%5E2-4x%2B8%29 expands to 4x%5E3-21x%5E2%2B52x-40.


In other words, %284x-5%29%28x%5E2-4x%2B8%29=4x%5E3-21x%5E2%2B52x-40.