helpppppppppppppppppppppppppppppppppppppppp

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helpppppppppppppppppppppppppppppppppppppppp
helpppppppppppppppppppppppppppppppppppppppp

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Mộc Miên 9 months 2021-05-10T18:40:47+00:00 2 Answers 12 views 0

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    0
    2021-05-10T18:42:01+00:00

    Đáp án + Giải thích các bước giải:

    a) `3x – 8 = 2(x – 4) + 5` $\\$ `<=> 3x-8=2x-8+5` $\\$ `<=>3x-8-2x+8-5=0` $\\$ `<=>x – 5 = 0 <=> x = 5`

    Vậy `S = {5}`

    b) `x^2 + 5x – 6 = 0` $\\$ `<=> x^2-x + 6x – 6 = 0` $\\$ `<=> x(x – 1) + 6(x – 1) = 0` $\\$ `<=> (x – 1)(x + 6) = 0 <=> `\(\left[ \begin{array}{l}x=1\\x=-6\end{array} \right.\)

    Vậy `S = {1;-6}`

    c) `3/(x + 1) – 2/(x – 2) = (4x – 2)/[(x + 1)(x – 2)](x ne -1,x ne 2)` $\\$ `<=> [3(x – 2)]/[(x+1)(x-2)] – [2(x+1)]/[(x+1)(x-2)] = (4x – 2)/[(x + 1)(x – 2)]` $\\$ `=> 3(x – 2) – 2(x + 1) = 4x – 2` $\\$ `<=> 3x – 6 – 2x – 2 – 4x + 2 = 0` $\\$ `<=> -3x – 6 = 0` $\\$ `<=> -3x = 6 <=> x = -2(TMĐK)`

    Vậy `S = {-2}`

    d) `|2x – 5| = x + 2`

    `<=> `\(\left[ \begin{array}{l}2x-5=x+2\\-(2x-5)=x+2\end{array} \right.\) $\\$ `<=> ` \(\left[ \begin{array}{l}2x-5-x-2=0\\-2x+5-x-2=0\end{array} \right.\) $\\$ `<=> ` \(\left[ \begin{array}{l}x-7=0\\-3x + 3 = 0\end{array} \right.\) $\\$ `<=> `\(\left[ \begin{array}{l}x=7\\x = 1\end{array} \right.\)

    Vậy `S = {7;1}`

    0
    2021-05-10T18:42:39+00:00

    Đây nhé bạn chúc bạn học tốt ^^

    helpppppppppppppppppppppppppppppppppppppppp

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )