Find all the rational roots of f(x)

label Algebra
account_circle Unassigned
schedule 1 Day
account_balance_wallet $5

F(x)= x3+8x2-x-8

Apr 30th, 2015

ANSWER =  ROOTS ARE     -1,  1 , -8


F(x)= x^3+8 x^2-x-8

      =(x^3+8 x^2)+(−x−8)

        =x^2(x+8)−1(x+8)

        =(x^2−1)(x+8)

 a^2 - b^2 = (a+ b)(a - b)

 so,

(x^2−1^2) = (x+1) (x -1)

substituting this in the above equation

F(x)= (x^2−1)(x+8)

       =(x+1) (x -1)(x+8).....


so  (x+1)=0    or  (x -1) = 0     or         (x+8) = 0

       x = -1     or   x = 1             or           x = - 8


thus the roots are  -1, 1 , -8..................................ANSWER



Apr 30th, 2015

Did you know? You can earn $20 for every friend you invite to Studypool!
Click here to
Refer a Friend
...
Apr 30th, 2015
...
Apr 30th, 2015
Sep 19th, 2017
check_circle
Mark as Final Answer
check_circle
Unmark as Final Answer
check_circle
Final Answer

Secure Information

Content will be erased after question is completed.

check_circle
Final Answer