Tính 9x^2 – 4=0 Ngoài lề:

Question

Tính
9x^2 – 4=0
Ngoài lề:
tinh-9-2-4-0-ngoai-le

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Trung Dũng 5 years 2021-05-16T03:25:16+00:00 2 Answers 29 views 0

Answers ( )

  1. ThanhThu
    0
    2021-05-16T03:26:18+00:00
    Reply

    `9x^2 – 4 = 0`

    `⇒ (3x)^2 – 2^2 = 0`

    `⇒ (3x + 2)(3x – 2) = 0`

    `⇒` \(\left[ \begin{array}{l}3x +2=0\\3x-2=0\end{array} \right.\)

    `⇒` \(\left[ \begin{array}{l}x=\frac{2}3\\x=-\frac{2}3\end{array} \right.\) 

    Vậy `S = {±2/3}`

     

  2. Nick
    0
    2021-05-16T03:27:13+00:00
    Reply

    Đáp án+Giải thích các bước giải:

    `9x^2-4=0`

    `<=>9x^2=4`

    `<=>x^2=4/9`

    `<=>x=+-2/3`

    Vậy `S={2/3,-2/3}`

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