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

Toán Lớp 8: cho a+b+c=0,abc khác 0. TÍnh G = ab/a^2+b^2 – c^2 + bc/b^2 +c^2 -a^2 + ca/ c2 +a^2 -b^2

Toán Lớp 8: cho a+b+c=0,abc khác 0. TÍnh G = ab/a^2+b^2 – c^2 + bc/b^2 +c^2 -a^2 + ca/ c2 +a^2 -b^2

Comments ( 1 )

  1. $\\$
    a+b+c=0
    => a=-b-c
    => a^2 = b^2+2bc+c^2
    => b^2+c^2 – a^2=-2bc
    a+b+c=0
    =>b=-a-c
    =>b^2=a^2+2ac+c^2
    => a^2+c^2-b^2=-2ac
    a+b+c=0
    =>c=-a-b
    =>c^2=a^2+2ab+b^2
    =>a^2+b^2-c^2=-2ab
    G=(ab)/(-2ab) +(bc)/(-2bc) + (ca)/(-2ca)
    = (-1)/2 +(-1)/2 +(-1)/2
    = (-3)/2
    Vậy G=(-3)/2

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

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