What are the possible integral zeros of P(x)=x^3+3x^2-6x-8P(x)=x3+3x2−6x−8?
1 Answer
Jan 5, 2018
Explanation:
"note that "note that
f(2)=8+12-12-8=0f(2)=8+12−12−8=0
rArr(x-2)" is a factor"⇒(x−2) is a factor
color(red)(x^2)(x-2)color(magenta)(+2x^2)+3x^2-6x-8x2(x−2)+2x2+3x2−6x−8
=color(red)(x^2)(x-2)color(red)(+5x)(x-2)color(magenta)(+10x)-6x-8=x2(x−2)+5x(x−2)+10x−6x−8
=color(red)(x^2)(x-2)color(red)(+5x)(x-2)color(red)(+4)(x-2)cancel(color(magenta)(+8))cancel(-8)
rArrx^3+3x^2-6x-8
=(x-2)(x^2+5x+4)
=(x-2)(x+1)(x+4)=0
rArrx=-4,x=-1" and "x=2larrcolor(blue)"are the zeros"