(x-3)^2 = 16 5^2x-1 = 125

Question

(x-3)^2 = 16
5^2x-1 = 125

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Latifah 6 years 2020-11-21T13:45:02+00:00 2 Answers 80 views 0

Answers ( )

  1. Acacia
    0
    2020-11-21T13:46:23+00:00
    Reply

    Đáp án:

     

    Giải thích các bước giải:

    $a)(x-3)^2=16_{}$ 

    $⇔(x-3)^2-4^2=0_{}$

    $⇔(x-3-4)(x-3+4)=0_{}$

    $⇔(x-7)(x+1)=0_{}$

    ⇔\(\left[ \begin{array}{l}x-7=0\\x+1=0\end{array} \right.\) $⇔_{}$ \(\left[ \begin{array}{l}x=7\\x=-1\end{array} \right.\)

    $b)5^{2x+1}=125_{}$

    $⇔5^{2x-1}=5^3_{}$

    $⇔2x-1=3_{}$

    $⇔2x=3+1_{}$

    $⇔2x=4_{}$

    $⇔x=2_{}$

  2. Sigrid
    0
    2020-11-21T13:46:53+00:00
    Reply

    a, $(x-3)^{2}$ = 16

        $(x-3)^{2}$ = $4^{2}$

    ⇒ \(\left[ \begin{array}{l}x-3=4\\x-3= -4\end{array} \right.\) 

    ⇒ \(\left[ \begin{array}{l}x=7\\x=-1\end{array} \right.\) 

    Vậy x ∈ { 7; -1 }.

    b, $5^{2x-1}$ = 125

    $5^{2x-1}$ = $5^{3}$ 

    ⇒ 2x – 1 = 3

        2x = 3 + 1

        2x = 4

         x = 4 : 2

         x = 2

    Vậy x = 2.

     

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