Square roots in quadratic equation












1














$${sqrt x}+ frac{8}{sqrt x} = 6$$



I'm trying to get this to the standard quadratic form so I can factorise it, but not sure how to eliminate the square roots/work around them.
Any help would be appreciated :)










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  • Substitute $t=sqrt{x}$
    – Matko
    26 mins ago










  • What do you get by squaring both sides?
    – Dietrich Burde
    25 mins ago










  • Just pay attention to the fact that when you substitute $;t:=sqrt x;$ , the solutions you take must be non-negative, as we have by agreement that $;sqrt xge0;$ .
    – DonAntonio
    10 mins ago










  • But if it was a cubic, would it be ok to have a negative answer?
    – Ma Ha
    6 mins ago
















1














$${sqrt x}+ frac{8}{sqrt x} = 6$$



I'm trying to get this to the standard quadratic form so I can factorise it, but not sure how to eliminate the square roots/work around them.
Any help would be appreciated :)










share|cite|improve this question







New contributor




Ma Ha is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.




















  • Substitute $t=sqrt{x}$
    – Matko
    26 mins ago










  • What do you get by squaring both sides?
    – Dietrich Burde
    25 mins ago










  • Just pay attention to the fact that when you substitute $;t:=sqrt x;$ , the solutions you take must be non-negative, as we have by agreement that $;sqrt xge0;$ .
    – DonAntonio
    10 mins ago










  • But if it was a cubic, would it be ok to have a negative answer?
    – Ma Ha
    6 mins ago














1












1








1







$${sqrt x}+ frac{8}{sqrt x} = 6$$



I'm trying to get this to the standard quadratic form so I can factorise it, but not sure how to eliminate the square roots/work around them.
Any help would be appreciated :)










share|cite|improve this question







New contributor




Ma Ha is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











$${sqrt x}+ frac{8}{sqrt x} = 6$$



I'm trying to get this to the standard quadratic form so I can factorise it, but not sure how to eliminate the square roots/work around them.
Any help would be appreciated :)







quadratics






share|cite|improve this question







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Ma Ha is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|cite|improve this question







New contributor




Ma Ha is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|cite|improve this question




share|cite|improve this question






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asked 27 mins ago









Ma Ha

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163




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New contributor





Ma Ha is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Ma Ha is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












  • Substitute $t=sqrt{x}$
    – Matko
    26 mins ago










  • What do you get by squaring both sides?
    – Dietrich Burde
    25 mins ago










  • Just pay attention to the fact that when you substitute $;t:=sqrt x;$ , the solutions you take must be non-negative, as we have by agreement that $;sqrt xge0;$ .
    – DonAntonio
    10 mins ago










  • But if it was a cubic, would it be ok to have a negative answer?
    – Ma Ha
    6 mins ago


















  • Substitute $t=sqrt{x}$
    – Matko
    26 mins ago










  • What do you get by squaring both sides?
    – Dietrich Burde
    25 mins ago










  • Just pay attention to the fact that when you substitute $;t:=sqrt x;$ , the solutions you take must be non-negative, as we have by agreement that $;sqrt xge0;$ .
    – DonAntonio
    10 mins ago










  • But if it was a cubic, would it be ok to have a negative answer?
    – Ma Ha
    6 mins ago
















Substitute $t=sqrt{x}$
– Matko
26 mins ago




Substitute $t=sqrt{x}$
– Matko
26 mins ago












What do you get by squaring both sides?
– Dietrich Burde
25 mins ago




What do you get by squaring both sides?
– Dietrich Burde
25 mins ago












Just pay attention to the fact that when you substitute $;t:=sqrt x;$ , the solutions you take must be non-negative, as we have by agreement that $;sqrt xge0;$ .
– DonAntonio
10 mins ago




Just pay attention to the fact that when you substitute $;t:=sqrt x;$ , the solutions you take must be non-negative, as we have by agreement that $;sqrt xge0;$ .
– DonAntonio
10 mins ago












But if it was a cubic, would it be ok to have a negative answer?
– Ma Ha
6 mins ago




But if it was a cubic, would it be ok to have a negative answer?
– Ma Ha
6 mins ago










2 Answers
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4














Hint: change variable $y = sqrt{x}$ .
$$y + frac{8}{y} = 6 Rightarrow y^2- 6y + 8 = 0 Rightarrow (y-2)(y-4) = 0 Rightarrow y in {2, 4} Rightarrow sqrt{x} = 2, 4Rightarrow x in {4,16}$$






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    3














    Yor equation is equivalent to $$x+8=6sqrt{x}$$ with $$t=sqrt{x}$$ we get $$t^2-6t+8=0$$






    share|cite|improve this answer





















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      2 Answers
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      2 Answers
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      active

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      4














      Hint: change variable $y = sqrt{x}$ .
      $$y + frac{8}{y} = 6 Rightarrow y^2- 6y + 8 = 0 Rightarrow (y-2)(y-4) = 0 Rightarrow y in {2, 4} Rightarrow sqrt{x} = 2, 4Rightarrow x in {4,16}$$






      share|cite|improve this answer


























        4














        Hint: change variable $y = sqrt{x}$ .
        $$y + frac{8}{y} = 6 Rightarrow y^2- 6y + 8 = 0 Rightarrow (y-2)(y-4) = 0 Rightarrow y in {2, 4} Rightarrow sqrt{x} = 2, 4Rightarrow x in {4,16}$$






        share|cite|improve this answer
























          4












          4








          4






          Hint: change variable $y = sqrt{x}$ .
          $$y + frac{8}{y} = 6 Rightarrow y^2- 6y + 8 = 0 Rightarrow (y-2)(y-4) = 0 Rightarrow y in {2, 4} Rightarrow sqrt{x} = 2, 4Rightarrow x in {4,16}$$






          share|cite|improve this answer












          Hint: change variable $y = sqrt{x}$ .
          $$y + frac{8}{y} = 6 Rightarrow y^2- 6y + 8 = 0 Rightarrow (y-2)(y-4) = 0 Rightarrow y in {2, 4} Rightarrow sqrt{x} = 2, 4Rightarrow x in {4,16}$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered 26 mins ago









          OmG

          2,052617




          2,052617























              3














              Yor equation is equivalent to $$x+8=6sqrt{x}$$ with $$t=sqrt{x}$$ we get $$t^2-6t+8=0$$






              share|cite|improve this answer


























                3














                Yor equation is equivalent to $$x+8=6sqrt{x}$$ with $$t=sqrt{x}$$ we get $$t^2-6t+8=0$$






                share|cite|improve this answer
























                  3












                  3








                  3






                  Yor equation is equivalent to $$x+8=6sqrt{x}$$ with $$t=sqrt{x}$$ we get $$t^2-6t+8=0$$






                  share|cite|improve this answer












                  Yor equation is equivalent to $$x+8=6sqrt{x}$$ with $$t=sqrt{x}$$ we get $$t^2-6t+8=0$$







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered 21 mins ago









                  Dr. Sonnhard Graubner

                  72.5k32865




                  72.5k32865






















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