SOLUTION: how do I Factor x^4 + 5x^3 – 84x^2

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: how do I Factor x^4 + 5x^3 – 84x^2       Log On


   

Question 215251: how do I Factor x^4 + 5x^3 – 84x^2
Found 2 solutions by vleith, drj:
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E4+%2B+5x%5E3+%96+84x%5E2+ first factor out the common term
x%5E2%28x%5E2+%2B+5x+-84%29 Now factor the quadratic
x%5E2%28x%2B12%29%28x-7%29
Here's a good URl to help you check your factoring answers
http://72.3.253.76:8080/webMathematica3/quickmath/page.jsp?s1=algebra&s2=factor&s3=basic

Answer by drj(1380) About Me  (Show Source):
You can put this solution on YOUR website!
How do I factor

x%5E4%2B5x%5E3-84x%5E2

Step 1. Look for common factors in each term. In this case it is x%5E2:

x%5E4%2B5x%5E3-84x%5E2=x%5E2%2A%28x%5E2%2B5x-84%29

Step 2. For the trinomial expression, need to find two integers m and n such that m+n=5 and m*n=-84.

Step 3. After trying several numbers, the integers are m=12 and n=-7.

x%5E2%2B5x-84=%28x%2B12%29%28x-7%29

Step 4. ANSWER. x%5E2%2A%28x%5E2%2B5x-84%29=x%5E2%28x%2B12%29%28x-7%29

I hope the above steps were helpful.

For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra or for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.

And good luck in your studies!

Respectfully,
Dr J