SOLUTION: How to factor8x^4-14x^2+3

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: How to factor8x^4-14x^2+3      Log On


   



Question 1045631: How to factor8x^4-14x^2+3
Found 2 solutions by ikleyn, MathTherapy:
Answer by ikleyn(52835) About Me  (Show Source):
You can put this solution on YOUR website!
.
How to factor 8x^4-14x^2+3
~~~~~~~~~~~~~~~~~~~~~~~

1.  Introduce new variable  u = x%5E2.
    Then the polynomial takes the form  8u%5E2-14u%2B3.

2.  Find the roots of the polynomial  8u%5E2-14u%2B3.

    For it, solve the quadratic equation  8u%5E2-14u%2B3 = 0.

    Use the quadratic formula. You will get 

    u%5B1%2C2%5D = %2814+%2B-+sqrt%2814%5E2+-+4%2A8%2A3%29%29%2F%282%2A8%29 = %2814+%2B-+10%29%2F16.

    So,  u%5B1%5D = 3%2F2  and  u%5B2%5D = 1%2F4.


3.  Hence, the quadratic polynomial  8u%5E2-14u%2B3  is

    8u%5E2-14u%2B3 = 8%2A%28u-3%2F2%29%2A%28u-1%2F4%29 = (2u-3)*(4u-1).

    Correspondingly,  the  original polynomial factorization is 

    8x%5E4-14x%5E2%2B3 = %282x%5E2-3%29%2A%284x%5E2-1%29.


4.  Next, you can factor further each of the two factors above to get

    8x%5E4-14x%5E2%2B3 = .


It is what you were asking for.


Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!

How to factor 8x^4-14x^2+3
8x%5E4+-+14x%5E2+%2B+3
8x%5E4+-+12x%5E2+-+2x%5E2+%2B+3 ------- Replacing matrix%281%2C3%2C+-+14x%5E2%2C+with%2C-+12x%5E2+-+2x%5E2%29
4x%5E2%282x%5E2+-+3%29+-+1%282x%5E2+-+3%29
%284x%5E2+-+1%29%282x%5E2+-+3%29
highlight_green%28%282x+-+1%29%282x+%2B+1%29%282x%5E2+-+3%29%29 ------- Factoring 4x%5E2+-+1 further