Tìm x: a) (x-1)^2=4 b) (x+2)^3=8

Question

Tìm x:
a) (x-1)^2=4
b) (x+2)^3=8

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Khang Minh 9 months 2020-10-28T21:24:15+00:00 2 Answers 84 views 0

Answers ( )

    0
    2020-10-28T21:25:55+00:00

    `a) (x-1)^2=4`

    `⇔(x-1)^2=2^2`

        `(x-1)^2=-2^2`

    `⇔x-1=2`

        `x-1 =-2`

    `⇒x=3`

        `x=-1`

    Vậy `x∈{3;-1}`

    `b) (x+2)^3=8`

    `⇔(x+2)^3=2^3`

    `⇔x+2=2`

    `⇒x=0`

    Vậy `x=0`

    `#Stduy well`

    0
    2020-10-28T21:26:04+00:00

    Đáp án:

     

    Giải thích các bước giải:

    a) `(x-1)^2=4`

    `⇔ (x-1)^2=2^2`

    `⇔` \(\left[ \begin{array}{l}x-1=2\\x-1=-2\end{array} \right.\)

    `⇔` \(\left[ \begin{array}{l}x=3\\x=-1\end{array} \right.\)

    Vậy `x=-1,x=3`

    b) `(x+2)^3=8`

    `⇔ (x+2)^3=2^3`

    `⇔ x+2=2`

    `⇔ x=0`

    Vậy `x=0`

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