if x=-1 is a root of x^3+2x^2-x-20 use synthetic division to factor the polynomial and it all real solution of the equation
i think the answer is (x+2)(x+1)^2 =-2-1

Question

if x=-1 is a root of x^3+2x^2-x-20 use synthetic division to factor the polynomial and it  all real solution of the equation
i think the answer is (x+2)(x+1)^2 =-2-1

anonymous · Answer

well did you do synthetic division?

rational · Answer

is that the complete problem ?

rational · Answer

i dont quite get what do u mean by x=-1 is a root x^3+2x^2-x-20
well x = -1 is NOT a root for that polynomial

anonymous · Answer

yes i did the synthetic division

anonymous · Answer

and what did you get?

anonymous · Answer

yes that the whole problem i dont get it either my teacher wrote it on the board and told us to do it

rational · Answer

another bad problem wid poor phrasing, you cant do it :/

rational · Answer

here are the roots of given polynomial : http://www.wolframalpha.com/input/?i=roots+of+x%5E3%2B2x%5E2-x-20

rational · Answer

-1 is not one of them

rational · Answer

so the input to problem itself is messed up

anonymous · Answer

alright i just wont do it then and hope the teacher will explain it . thank you for the help

rational · Answer

wait a sec, i think i found the mistake :)

rational · Answer

we can solve it if the polynomial is $ x^3+2x^2-x-2$
instead of $ x^3+2x^2-x-2\color{red}{0}$

rational · Answer

then it factors to : $x^2 + 2x^2 -x -2 = (x+1)(x-1)(x+2)$ http://www.wolframalpha.com/input/?i=factor+x%5E3%2B2x%5E2-x-2

rational · Answer

just check once if u have copied the polynomial correctly