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

Toán Lớp 8: thu gọn phân thức: (x^2).(1/x-1-1/x+1-1)

Toán Lớp 8: thu gọn phân thức: (x^2).(1/x-1-1/x+1-1)

Comments ( 1 )

  1. Giải đáp:
    = – x^2 + 3
    Lời giải và giải thích chi tiết:
     (x^2 – 1)(1/{x – 1} – 1/{x + 1} – 1)
    = (x^2 – 1)({x + 1}/{(x – 1)(x+1)} – {x-1}/{(x-1)(x + 1)} – 1)
    = (x^2 – 1)({x + 1- (x – 1)}/{(x – 1)(x+1)} – 1)
    = (x^2 – 1)({x + 1- x + 1}/{(x – 1)(x+1)} – 1)
    = (x^2 – 1)({2}/{(x – 1)(x+1)} – 1)
    = (x^2 – 1)({2}/{x^2 – 1} – 1)
    = (x^2 – 1)(2/{x^2 – 1}) – 1.(x^2 – 1)
    = (x^2 – 1)(2/{x^2 – 1}) – 1.(x^2 – 1)
    = 2 – (x^2 – 1)
    = 2 – x^2 + 1 = – x^2 + (2 + 1)
    = – x^2 + 3
    #SunHee

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