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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: tìm x: (x-4)^2-(x-2)*(x+2)=6 giúp mình với ạ

Toán Lớp 8: tìm x: (x-4)^2-(x-2)*(x+2)=6
giúp mình với ạ

Comments ( 2 )

  1. (x-4)^2-(x-2)xx(x+2)=6
    ⇔ x^2−8x+16−(x−2)(x+2)=6
    ⇔ x^2−8x+16−(x^2−4)=6
    ⇔ x^2−8x+16−x^2+4=6
    ⇔ −8x+16+4=6
    ⇔ −8x+20=6
    ⇔ −8x=6−20
    ⇔ −8x=−14
    ⇒ x = (-14)/(-8)
    x = 7/4
    Cho mình xin hay nhất nha bạn
    @Drew Mclntyre

  2. ***Lời giải***
    (x-4)^2-(x-2)(x+2)=6
    <=>x^2+16-8x-(x^2-4)=6
    <=>x^2+16-8x-x^2+4=6
    <=>x^2-8x-x^2=6-16-4
    <=>-8x=-14
    <=>x=7/4
    Vậy S={7/4}

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222-9+11+12:2*14+14 = ? ( )