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

Toán Lớp 8: 3/x^2+2xy+y^2 + 4/2xy-x^2-y^2 + 5/x^2y^2

Toán Lớp 8: 3/x^2+2xy+y^2 + 4/2xy-x^2-y^2 + 5/x^2y^2

Comments ( 1 )

  1. Lời giải và giải thích chi tiết:
    ta có:
    $\frac{3}{x²+2xy+y²}+ \frac{4}{2xy-x²-y²}+\frac{5}{x^2-y^2}\\=\frac{3}{(x+y)²}-\frac{4}{(x-y)^2}+\frac{5}{x^2-y^2}\\=\frac{3(x-y)^2-4(x+y)^2}{(x^2-y^2)(x^2+y^2)} +\frac{5}{x^2-y^2}$
    $=\frac{3(x-y)^2-4(x+y)^2+5(x^2+y^2)}{x^4-y^4}\\=\frac{8(x-y)^2-4(x+y)^2}{x^4-y^4}\\=\frac{8x^2-16xy+8y^2-4x^2-8xy-4y^2}{x^4-y^4}\\=\frac{4x^2+4y^2-32xy}{x^4-y^4}$
    chịu mk ra tới đây ak 

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