tìm x: 1. (x-2) mũ 2 = 1 2. (x+1/2) mũ 2 = 1/4 3. (3x-1) mũ 3 = -8/27 4. (2x+3 )mũ 2 = 9/121 5.(2x-1)mũ 3 =27

0 bình luận về “tìm x: 1. (x-2) mũ 2 = 1 2. (x+1/2) mũ 2 = 1/4 3. (3x-1) mũ 3 = -8/27 4. (2x+3 )mũ 2 = 9/121 5.(2x-1)mũ 3 =27”

1.  `1, (x-2)² = 1`

   `⇔ (x-2)² = (±1)²`

   `⇔`\(\left[ \begin{array}{l}x-2=1 \\ x-2= -1\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}x=3\\x=1\end{array} \right.\) 

   `2, (x+1/2)² = 1/4`

   `⇔(x+1/2)² = (±1/2)²`

   `⇔`\(\left[ \begin{array}{l}x+\dfrac{1}{2}=\dfrac{1}{2} \\x+\dfrac{1}{2}=\dfrac{-1}{2}\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}x=0\\x=-1\end{array} \right.\) 

   `3, (3x-1)³ = -8/27`

   `⇔(3x-1)³ = (-2/3)³`

   `⇔3x-1 = -2/3`

   `⇔3x = 1/3`

   `⇔x = 1/9`

   `4, (2x+3)² = 9/121`

   `⇔(2x+3)² = (±3/11)²`

   `⇔`\(\left[ \begin{array}{l}2x+3=\dfrac{3}{11} \\x+\dfrac{1}{2}=\dfrac{-1}{2}\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}2x =\dfrac{-30}{11}\\2x=\dfrac{-36}{11}\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}x=\dfrac{-15}{11}\\x=\dfrac{-18}{11}\end{array} \right.\)

   `5, (2x-1)³ =27`

   `⇔ (2x-1)³ = 3³`

   `⇔ 2x-1=3`

   `⇔ 2x=4`

   `⇔ x=2`

    

   Trả lời

2. Đáp án:

    

   Giải thích các bước giải:

   1. (x-2)² = 1

   ⇒(x-2)² = (±1)²

   ⇒x-2=1 ⇔x=3

      hoặc x-2= -1 ⇔x=1

   2. (x+1/2)² = 1/4

   ⇒(x+1/2)² = (±1/2)²

   ⇒x+1/2=1/2 ⇔x=0

       hoặc x+1/2= -1/2 ⇔x= -1

   3. (3x-1)³ = -8/27

   ⇒(3x-1)³ = (-2/3)³

   ⇒3x-1 = -2/3

   ⇒3x = 1/3

   ⇒x = 1/9

   4. (2x+3)² = 9/121

   ⇒(2x+3)² = (±3/11)²

   ⇒2x+3 = 3/11 ⇔2x= -30/11 ⇔x= -15/11

       hoặc 2x+3= -3/11 ⇔2x= -36/11 ⇔x= -18/11

   5. (2x-1)³ =27

   ⇒(2x-1)³ = 3³

   ⇒2x-1=3

   ⇒2x=4

   ⇒x=2

    

   Trả lời