SOLUTION: one solution of x^3-5x^2+5x-1=0 is 1. find the other two solutions. if anyone can help me with that problem i would really appreciate them. thank you all again:)

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: one solution of x^3-5x^2+5x-1=0 is 1. find the other two solutions. if anyone can help me with that problem i would really appreciate them. thank you all again:)      Log On


   



Question 280378: one solution of x^3-5x^2+5x-1=0 is 1. find the other two solutions.
if anyone can help me with that problem i would really appreciate them. thank you all again:)

Found 2 solutions by checkley77, richwmiller:
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
Seeing as one of the answers is x=1 then we have:
%28x%5E3-5x%5E2%2B5x-1%29%2F%28x-1%29
&&&x^2-4x+1
&&&_________________
(x-1)| x^3-5x^2+5x-1=0
&&& x^3-x^2
&&&&--------
&&&&&-4x^2+5x
&&&&&-4x^2+4x
&&&&&&--------
&&&&&&&+1x-1
&&&&&&&+1x-1
&&&&&&&-----
&&&&&&&&&0
(x-1)(x^2-4x+1)=0
USING THE QUADRATIC EUATION FOR (X^2-4X+1) WE GET:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
X=3.732 & X=.268

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
If x=1 is one solution that means that x-1 is one factor
so you need to divide the equation by (x-1) to get the other factor
to get (x-1) (x^2-4x+1) = 0
now we use the quadratic formula to solve for the other two solutions(roots)
exact forms
x = 2-sqrt(3)
x = 2+sqrt(3)
the approximate forms are given below
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B-4x%2B1+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-4%29%5E2-4%2A1%2A1=12.

Discriminant d=12 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--4%2B-sqrt%28+12+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-4%29%2Bsqrt%28+12+%29%29%2F2%5C1+=+3.73205080756888
x%5B2%5D+=+%28-%28-4%29-sqrt%28+12+%29%29%2F2%5C1+=+0.267949192431123

Quadratic expression 1x%5E2%2B-4x%2B1 can be factored:
1x%5E2%2B-4x%2B1+=+1%28x-3.73205080756888%29%2A%28x-0.267949192431123%29
Again, the answer is: 3.73205080756888, 0.267949192431123. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-4%2Ax%2B1+%29