How do you factor x^4+6x^3-36x^2-216xx4+6x3−36x2−216x?
1 Answer
May 22, 2017
Explanation:
x^4+6x^3-36x^2-216xx4+6x3−36x2−216x
=x(x^3+6x^2-36x-216)larr" common factor " x=x(x3+6x2−36x−216)← common factor x
"note that when " x=6note that when x=6
x^3+6x^2-36x-216=0x3+6x2−36x−216=0
rArrx=6" is a root and hence " (x-6)" is a factor"⇒x=6 is a root and hence (x−6) is a factor
rArrx^2(x-6)+12x(x-6)+36(x-6)⇒x2(x−6)+12x(x−6)+36(x−6)
=(x-6)(x^2+12x+36)=(x−6)(x2+12x+36)
=(x-6)(x+6)(x+6)=(x−6)(x+6)(x+6)
rArrx^4+6x^3-36x^2-216x=x(x-6)(x+6)^2⇒x4+6x3−36x2−216x=x(x−6)(x+6)2