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

Toán Lớp 8: Tính a, $\frac{2}{x+y}$ + $\frac{1}{x-y}$ + $\frac{3}{y^2-x^2}$ b, $\frac{x}{2-2x}$ + $\frac{x^2+1}{2-2x^2}$

Home/ Toán Lớp 8: Tính a, $\frac{2}{x+y}$ + $\frac{1}{x-y}$ + $\frac{3}{y^2-x^2}$ b, $\frac{x}{2-2x}$ + $\frac{x^2+1}{2-2x^2}$

Toán Lớp 8: Tính a, $\frac{2}{x+y}$ + $\frac{1}{x-y}$ + $\frac{3}{y^2-x^2}$ b, $\frac{x}{2-2x}$ + $\frac{x^2+1}{2-2x^2}$

Tháng Chín 19, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: Tính
a, $\frac{2}{x+y}$ + $\frac{1}{x-y}$ + $\frac{3}{y^2-x^2}$
b, $\frac{x}{2-2x}$ + $\frac{x^2+1}{2-2x^2}$

Comments ( 2 )

  1. khanhngantoan
    khanhngantoan
    19 Tháng Chín, 2022 at 11:13 chiều
    Reply
    $\text{ @HV }$
    $\text{ a) $\frac{2}{x + y}$ + $\frac{1}{x – y}$ + $\frac{3}{y^2 – x^2}$ }$
    $\text{ = $\frac{2}{x + y}$ + $\frac{1}{x – y}$ – $\frac{3}{x^2 – y^2}$ }$
    $\text{ = $\frac{2}{x + y}$ + $\frac{1}{x – y}$ – $\frac{3}{(x – y).(x + y)}$ }$
    $\text{ = $\frac{2x – 2y}{(x + y).(x – y)}$ + $\frac{x + y}{(x – y).(x + y)}$ – $\frac{3}{(x – y).(x + y)}$ }$
    $\text{ = $\frac{2x – 2y + x + y – 3}{(x – y).(x + y)}$ }$
    $\text{ = $\frac{3x – y – 3}{x^2 – y^2}$ }$
    $\text{ b) $\frac{x}{2 – 2x}$ + $\frac{x^2 + 1}{2 – 2x^2}$ }$
    $\text{ = $\frac{x}{2.(1 – x)}$ + $\frac{x^2 + 1}{2.(1 – x^2)}$ }$
    $\text{ = $\frac{x}{2.(1 – x)}$ + $\frac{x^2 + 1}{2.(1-x).(1+x)}$ }$
    $\text{ = $\frac{x + x^2 + x^2 + 1}{2.(1 – x).(1 + x)}$ }$
    $\text{ = $\frac{x + 2x^2 +1}{2.(1-x).(1+x)}$ }$
     

  2. mocmien87
    mocmien87
    19 Tháng Chín, 2022 at 11:13 chiều
    Reply
    Giải đáp+Lời giải và giải thích chi tiết:
     a) 2/(x+y)+1/(x-y)+3/(y^2-x^2) ĐK: x\ne+-y; y\ne-x
    =2/(x+y)+1/(x-y)-3/((x-y)(x+y))
    =(2(x-y)+(x+y)-3)/((x-y)(x+y))
    =(2x-2y+x+y-3)/((x-y)(x+y))
    =(3x-y-3)/((x-y)(x+y))
     b) x/(2-2x)+(x^2+1)/(2-2x^2) ĐK: x\ne+-1
    =x/(2(1-x))+(x^2+1)/(2(1-x^2))
    =x/(2(1-x))+(x^2+1)/(2(1-x)(1+x))
    =(x(1+x)+x^2+1)/(2(1-x)(1+x))
    =(x+x^2+x^2+1)/(2(1-x)(1+x))
    =(2x^2+x+1)/(2(1-x)(1+x))

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

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