(x+1)^2-5=x^2+11 x-5x/6+1/3=2-x/3 x-2/3-2x-3/4=x-1 Giúp mình giải với ạ

Question

(x+1)^2-5=x^2+11
x-5x/6+1/3=2-x/3
x-2/3-2x-3/4=x-1
Giúp mình giải với ạ

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Valerie 1 tháng 2021-08-05T01:35:27+00:00 2 Answers 5 views 0

Answers ( )

    0
    2021-08-05T01:36:52+00:00

    `#DyHungg`

    `a) (x+1)²-5=x²+11`

    `⇔x²+2x+1-5=x²+11`

    `⇔x²-x²+2x=-1+5+11`

    `⇔2x=15`

    `⇔x=15/2`

    Vậy S={15/2}`

    `b) (x-5x)/6+1/3=(2-x)/3`

    `⇔(3(x-5x))/18+6/18=(6(2-x))/18`

    `⇔3x-15x+6=12-6x`

    `⇔3x-15x+6x=12-6`

    `⇔-6x=6`

    `⇔x=-1`

    Vậy `S={-1}`

    `c) (x-2)/3-(2x-3)/4=x-1`

    `⇔(4(x-2))/12-(3(2x-3))/12=(12(x-1))/12`

    `⇔4x-8-6x+9=12x-12`

    `⇔4x-6x-12x=8-9-12`

    `⇔-14x=-13`

    `⇔x=13/14`

    Vậy `S={13/14}`

    0
    2021-08-05T01:37:26+00:00

    Đáp án: + Giải thích các bước giải:

    `a//`

    `(x+1)^2 – 5 = x^2 + 11`

    `\Leftrightarrow x^2 + 2x = x^2 + 15`

    `\Leftrightarrow x^2 + 2x – x^2 = x^2 + 15 – x^2`

    `\Leftrightarrow 2x = 15`

    `\Leftrightarrow x = 15/2`

    Vậy `S = { 15/2 }`

    `b//`

    `(x-5x)/6 + 1/3 = (2-x)/3`

    `\Leftrightarrow (x-5x)/6 + 2/6 = (2(2-x))/6`

    `\Leftrightarrow (x-5x) + 2 = 2(2-x)`

    `\Leftrightarrow -4x + 2 = -2x + 4`

    `\Leftrightarrow -4x – 2x = 2`

    `\Leftrightarrow -2x = 2`

    `\Leftrightarrow x = -1`

    Vậy `S = { – 1 }`

    `c//`

    `(x-2)/3 – (2x-3)/4 = x – 1`

    `\Leftrightarrow 4(x-2) – 3(2x-3) = 12(x-1)`

    `\Leftrightarrow 4x – 8 – 6x + 9 = 12x – 12`

    `\Leftrightarrow -2x + 1 = 12x – 12`

    `\Leftrightarrow -2x – 12 = 12x – 13 – 12x`

    `\Leftrightarrow -14x = -13`

    `\Leftrightarrow x = 13/14`

    Vậy `S = { 13/14 }`

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