Question

Medal to first who explains me this question :)
Find the roots of the equation (comment).

Answer 1

\[x ^{3}-x ^{2}-7x+3\]

Answer 2

k whats the question

Answer 3

ok do you want it factorized or what?

Answer 4

That's problem, I'm not quite sure what should I do :s

Answer 5

x^3+x^2-7x-3

One of the roots is x(1) = -3

After applying Polynomial remainder theorem you will have a second order equation

x^2 - 2x - 1 = 0

a = 1 ; b = -2 ; c = -1

x(2,3) = (-b)(+/-)SqRoot{b^2 - 4 . a . c}/(2 a)=

x(2,3) = (2)(+/-)SqRoot{4 - 4 . 1 . (-1)}/(2 . 1)=

x(2,3) = (2)(+/-)SqRoot{4 + 4}/(2)=

x(2,3) = 2 (+/-) SqRoot { 8 } / 2 =

x(2,3) = 1 (+/-) SqRoot { 2 }

---> x(2) = 1 + SqRoot { 2 }

---> x(3) = 1 - SqRoot { 2 }

Answer 6

u should do that but instead of doing minus you do the addition this was a mere example but close enough so that you would know what to do

Answer 7

I understand second part perfectly that's not problem :) can you just explain how did you get -3 as one of the roots? I'm bit confused

Answer 8

I just replaced +3 with -3 in this example

Answer 9

so in your case the root would be +3

Answer 10

Why is that?

Answer 11

capish? :)