Question 215251
{{{x^4 + 5x^3 – 84x^2 }}} first factor out the common term
{{{x^2(x^2 + 5x -84)}}} Now factor the quadratic
{{{x^2(x+12)(x-7)}}}
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