d) /x/=/-4/ h) 3/2x-1/=15 k) (x+12).(x.3)=0 i) /x/<5 m) 3.x mũ 3 -12+x mũ 3 =4+2.x mũ 3

0 bình luận về “d) /x/=/-4/ h) 3/2x-1/=15 k) (x+12).(x.3)=0 i) /x/<5 m) 3.x mũ 3 -12+x mũ 3 =4+2.x mũ 3”

1. Đáp án:

   `d)`

   l `x`l `= 4`

   ` =>x = 4` hoặc ` x = -4`

    ` h)`

   `3` l`2x-1`l `= 15`

   ` => l`2x-1`l `= 5`

   `=>` TH1

   ` 2X -1 = 5`

   => 2X = 6`

   ` => X= 3`

   TH2

   ` 2x -1 = -5`

   ` => 2x = -4`

   ` => x = -2`

   ` k)`

   ` (x+12).(x+3) = 0`

   ` => x +12 = 0` hoặc ` x+ 3 = 0`

   ` => x =-12` hoặc ` x = -3`

   ` i`

   l`x`l` <5`

   ` =>  x ∈ { -4;-3;-2;-1;0;1;2;3;4}`

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2. `d, |x|=|-4|`

   `|x|=4`

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

     Vậy `x=4` hoặc `x=-4`

   `h, 3|2x-1|=15`

   `|2x-1|=5`

   `<=>`\(\left[ \begin{array}{l}2x-1=5\\2x-1=-5\end{array} \right.\) 

   `<=>`\(\left[ \begin{array}{l}2x=6\\2x=-4\end{array} \right.\) 

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

      Vậy `x=3` hoặc `x=-2`

   `k, (x+12).(x.3)=0`

   `<=>`\(\left[ \begin{array}{l}x+12=0\\x.3=0\end{array} \right.\) 

   `<=>` \(\left[ \begin{array}{l}x=-12\\x=0\end{array} \right.\) 

       Vậy `x=-12` hoặc `x=0`

   `i, |x|<5`

   `+, |x|=0`

   `=> x=0`

   `+, |x|=1`

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

   `+, |x|=2`

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

   `+,|x|=3`

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

   `+,|x|=4`

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

      Vậy `x ∈`{`-4;-3;-2;-1;0;1;2;3;4`}

   `m,3.x³ -12+x³=4+2.x³`

   `3.x³+x³-2x³=-12+4`

   `x³.(2-1-2)=-12+4`

   `x³(-1)=-12+4`

   `x³=-8`

   `x³=2³`

   `=>x=2`

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