SOLUTION: Multiply: (x-4)(x^2+3x+5)

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Question 371280: Multiply: (x-4)(x^2+3x+5)
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
%28x-4%29%28x%5E2%2B3x%2B5%29
When multiplying polynomials you multiply each term of one polynomial by each term of the other. Then you add like terms, if any. I find it helps avoid errors if subtractions are rewritten as additions of the opposite:
%28x+%2B+%28-4%29%29%28x%5E2%2B3x%2B5%29
x%2Ax%5E2+%2B+x%2A3x+%2B+x%2A5+%2B+%28-4%29%2Ax%5E2+%2B+%28-4%29%2A3x+%2B+%28-4%29%2A5
Multiplying out we get:
x%5E3+%2B+3x%5E2+%2B+5x+%2B+%28-4%2Ax%5E2%29+%2B+%28-12x%29+%2B+%28-20%29
Adding like terms:
x%5E3+%2B+%28-1%2Ax%5E2%29+%2B+%28-7x%29+%2B+%28-20%29
or
x%5E3+-x%5E2+-7x+-20