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solving v. simple quartics like quadratics-trig on the side Watch

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    hey someone was trying to explain to me how you can solve v simple quartics by first factorising so it becomes quadratic and then just solving that. Which is great except that I cannot find the one example that he showed me

    so anyway I was looking online. I'm not sure if this is the exact way the person showed ne but anyway I was trying to follow this example online. Here it is


    x^4+6x^2+5

    so they change it into x^2 by writing (x^2)^2+6(x^2)+5

    however then they get : (x^2+5)(x^2+1)

    I don't know how they have managed to get this from the step above

    help would be appreciated will give rep but don't get toooo complicated with elaborate formulas as I don't need to know that
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    (Original post by CasualSoul)
    hey someone was trying to explain to me how you can solve v simple quartics by first factorising so it becomes quadratic and then just solving that. Which is great except that I cannot find the one example that he showed me

    so anyway I was looking online. I'm not sure if this is the exact way the person showed ne but anyway I was trying to follow this example online. Here it is


    x^4+6x^2+5

    so they change it into x^2 by writing (x^2)^2+6(x^2)+5

    however then they get : (x^2+5)(x^2+1)

    I don't know how they have managed to get this from the step above

    help would be appreciated will give rep but don't get toooo complicated with elaborate formulas as I don't need to know that
    Make a substitution u=x^2

    Now factorise u^2+6u+5

    Replace u.
 
 
 
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