2,tìm xEZ,biết: a,3x-5=2x+4 b,2×(3x-4)+7=5x-2 c,(x-3)²=16 d,(2x-1)³=-27

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1. Giải thích các bước giải:

   `a,3x-5=2x+4`
   `=>3x-2x=4+5`
   `=>x.(3-2)=9`
   `=>x.1=9`
   `=>x=9:1`
   `=>x=9`
   `b,2×(3x-4)+7=5x-2`
   `=>6x-8+7=5x-2`
   `=>6x-(8-7)=5x-2`
   `=>6x-1=5x-2`
   `=>6x-5x=-2+1`
   `=>x.1=-1`
   `=>x=-1:1`
   `=>x=-1`
   `c,(x-3)²=16`
   `=>(x-3)^2=(+-4)^2`
   `=>`\(\left[ \begin{array}{l}x-3=4\\x-3=-4\end{array} \right.\)
   `=>` \(\left[ \begin{array}{l}x=4+3\\x=-4+3\end{array} \right.\) 
   `=>`\(\left[ \begin{array}{l}x=7\\x=-1\end{array} \right.\)
   `d,(2x-1)³=-27`
   `=>(2x-1)^3=(-3)^3`
   `=>2x-1=-3`
   `=>2x=-3+1`
   `=>2x=-2`
   `=>x=-1`

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2. ` a) ` ` 3x – 5 = 2x + 4 `

   ` => 3x – 2x = 4 + 5 `

   ` => x = 9 `

   Vậy ` x = 9 `

   ` b) ` ` 2(3x – 4) + 7 = 5x – 2 `

   ` => 6x – 8 + 7 = 5x – 2 `

   ` => 6x – 5x = 8 – 7 – 2 ` 

   ` => x = -1 `

   Vậy ` x = -1 `

   ` c) ` ` (x – 3)^2 = 16 `

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

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

   Vậy ` x = 7 ` hoặc ` x = -1 `

   ` d) ` ` (2x – 1)^3 = -27 `

   ` => 2x – 1 = -3 `

   ` => 2x = -2 `

   ` => x = -1 `

   Vậy ` x = -1 `

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