STOP Making These Math Mistakes in Radical Equations

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  • Опубліковано 18 січ 2025

КОМЕНТАРІ • 7

  • @gregevgeni1864
    @gregevgeni1864 Місяць тому +2

    x = -1/2 or x = -2.
    Let p = √((2x+3)/(x+1)) and
    q = √((3x+2)/(x+1)) (*) with
    { (2x+3)/(x+1) ≥ 0 and (3x+2)/(x+1) ≥0 and x ≠ -1 } =>
    x ≤ -3/2 and -2/3 ≤ x (**).
    Now from (*) we have
    p² + q² = (2x+3)/(x+1)+(3x+2)/(x+1)
    = 5(x+1)/(x+1) =5 => p² + q² = 5 (1).
    From the original equation and (*) we have p³ +q³ = 9 (2).
    We solve the system of (1) and (2).
    (1) (p+q)² - 2(pq) = 5 (1)'
    (2) (p+q)³ -3(pq)(p+q) = 9 (2)'.
    Put p+q = r and pq = t and the system of the (1)' and (2)' rewrite as
    r² - 2t = 5 (1)'' and r³-3rt = 9 (2)''.
    From (1)'' => 2t = r² - 5 .
    The (2)'' write as 2r³ -3r(r²-5) =18 or
    2r³ -3r³+15r-18=0 or r³ - 15r +18 = 0 (r-3)(r²+3r-9)=0 =>
    r=3 or r=(-3±3√5)/2..
    From r=3 => t=2.
    So p+q =3 and pq =2 => p, q roots of the m² -3m+2=0 => m =1 or m=2 so (p,q)=(1,2) or (p,q)=(2,1).
    For p=1 => √((2x+3)/(x+1)) =1 =>
    (2x+3)/(x+1) =1 => x=-2 accepted
    due to (**).
    For p=2 => √((3x+2)/(x+1)) = 2 =>
    (2x+3)/(x+1) = 4 => x=-1/2 accepted due to (**).
    The solution x=-1/2 satisfies the given equation.
    We will work accordingly in the case that r = (-3±3√5)/2 .. 😅

  • @davidshen5916
    @davidshen5916 Місяць тому +1

    A=Sqrt((2X+3)/(X+1)), B=Sqrt((3X+2)/(X+1)), A^3+B^3=9, A^2+B^2=(2X+3)/(X+1)+(3X+2)/(X+1)=5, A=2, B=1, Or A=1,B=2

  • @ShriH-d1o
    @ShriH-d1o Місяць тому +1

    > a^3/2+b^3/2 =9 =8+1 or 1+8; =>
    {(2x+3)/(x+1)}^3/2=8 or1; =√(4^3) or√1^3=> (2x+3)(x+1)=4;=> 2x+3=4x+4;=> 2x=-1; x= -1/2; for
    (2x+3)/(x+1)=1;=>
    x = -2; verified for part b^3/2; ok; =>
    x = -1/2 or -2 .

  • @rabotaakk-nw9nm
    @rabotaakk-nw9nm Місяць тому

    8:00 vʼ(mn)=(11+3vʼ33)/4≈7.06
    mn≈50; Δ≈25-4•50≈-175

  • @RealQinnMalloryu4
    @RealQinnMalloryu4 Місяць тому

    {6x^3+12}/{x^3+3}+{12x^3+6}/{x^3+3}={18x^3/3x^3+18x^3/3x^3}=36x^6/6x^6=6x^1 2^3x^1 2^1x^1 2x^1 (x ➖ 2x+1).

  • @潘博宇-k4l
    @潘博宇-k4l Місяць тому

    X=-1/2 or -2.

  • @Fjfurufjdfjd
    @Fjfurufjdfjd Місяць тому

    χ=/-1.θετω (2χ+3)/(χ+1)=α>0 και β=(3χ+2)/(χ+1)>0. Τοτε α+β=5. Η εξισωση που δινεται γραφεται (α^3)^(1/2)+(β^3)^(1/2)=9. Υψωνω στο τετραγωνο και εχω: α^3+β^3+2(α^3β^3)^(1/2)=81.
    (α+β)^3-3αβ(α+β)+2([(αβ)^3]^(1/2)=81.
    125-15(αβ)+2[(αβ)^(1/2)]^3=81.
    Αν (αβ)^(1/2)=ψ>0 εχω:
    2ψ^3-15ψ^2+44=0 (ψ-2)(2ψ^2-11ψ-22)=0
    ψ=2 ή ψ=[11+(27×11)^(1/2)]/4 ψ>0.
    Ψ=2 (αβ)^(1/2)=2 αβ=4.αρα
    α+β=5 και αβ=4. α=1,β=4 ή α=4,β=1.χ=-2 ή χ=-1/2
    Αν αβ=(11/8)[19+3(33)^(1/2)] και α+β=5
    η εξισωση που προκυπτει δεν δινει πραγματικες λυσεις για τα α,β.
    Τελικα: χ=-2,-1/2.