Question 215256
How do I factor 


{{{x^4+5x^3-84x^2}}}


Step 1.  Look for common factors in each term.  In this case it is  {{{x^2}}}:


{{{x^4+5x^3-84x^2=x^2*(x^2+5x-84)}}}


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^2+5x-84=(x+12)(x-7)}}}


Step 4.  ANSWER.   {{{x^2*(x^2+5x-84)=x^2(x+12)(x-7)}}}


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