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

Toán Lớp 8: Tìm x (x-5)(x+5)-(x+3)^2+3(x-2)^2=(x+1)^2-(x+4)(x-4)+3x^2 giúp mik vs ạ đag gấp

Toán Lớp 8: Tìm x
(x-5)(x+5)-(x+3)^2+3(x-2)^2=(x+1)^2-(x+4)(x-4)+3x^2
giúp mik vs ạ đag gấp

Comments ( 2 )

  1. Lời giải:
    (x-5)(x+5)-(x+3)^(2)+3(x-2)^2=(x+1)^(2)-(x+4)(x-4)+3x^2
    ⇔x^(2)-5^(2)-(x^(2)+6x+9)+3(x^(2)-4x+4)=x^(2)+2x+1-x^(2)+16+3x^2
    ⇔x^(2)-25-x^(2)-6x-9+3x^(2)-12x+12=3x^(2)+2x+17
    ⇔3x^(2)-18x-22-3x^(2)-2x-17=0
    ⇔-20x-39=0
     ⇔x=-39/20
    Vậy x=-39/20

  2. Giải đáp: x=-39/20
    Lời giải và giải thích chi tiết:
    (x-5)(x+5)-(x+3)^2+3(x-2)^2=(x+1)^2-(x+4)(x-4)+3x^2
    ⇔x^2-25-(x^2+6x+9)+3(x^2-4x+4)=x^2+2x+1-(x^2-16)+3x^2
    ⇔x^2-25-x^2-6x-9+3x^2-12x+12=x^2+2x+1-x^2+16+3x^2
    ⇔3x^2-18x-22=3x^2+2x+17
    ⇔3x^2-18x-22-3x^2-2x-17=0
    ⇔-20x-39=0
    ⇔-20x=39
    ⇔x=-39/20
    Vậy x=-39/20

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

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