1) 3x+5=2x-4 2) x-7-(2x+1)=5 3) (2x-7)-(7x+5)=6 4) (x+3)-(2x+1)=5 5) x+2/3-x/2=x 6) x+7/2-x=1/2 7) (x-5)(x+3)=0 8) (x-3)(x+2)=0 9) x+1/1+1/2x=1/2 10)

0 bình luận về “1) 3x+5=2x-4 2) x-7-(2x+1)=5 3) (2x-7)-(7x+5)=6 4) (x+3)-(2x+1)=5 5) x+2/3-x/2=x 6) x+7/2-x=1/2 7) (x-5)(x+3)=0 8) (x-3)(x+2)=0 9) x+1/1+1/2x=1/2 10)”

1. Giải thích các bước giải:

    1) 3x+5=2x-4

   ⇒3x-2x=-4-5

   ⇒x=-9

   2) x-7-(2x+1)=5

   ⇒x-7-2x+1-5=0

   ⇒-x-11=0

   ⇒x=-11

   3) (2x-7)-(7x+5)=6

   ⇒2x-7-7x-5-6=0

   ⇒-5x=18

   ⇒x=$\frac{-18}{5}$ 

   4) (x+3)-(2x+1)=5

   ⇒x+3-2x-1-5=0

   ⇒-x=3

   ⇒x=-3

   5) x+$\frac{2}{3}$ -$\frac{x}{2}$ =x

   ⇒x+$\frac{2}{3}$ -$\frac{x}{2}$-x=0

   ⇒-$\frac{x}{2}$=-$\frac{2}{3}$

   ⇒x=$\frac{4}{3}$ 

   6) x+7/2-x=1/2

   ⇒0x=-3 (vô lí)

   7) (x-5)(x+3)=0

   ⇒x-5=0 hoặc x+3=0

   ⇒x=5 hoặc x=-3

   8) (x-3)(x+2)=0

   ⇒x-3=0 hoặc x+2=0

   ⇒x=3 hoặc x=-2

   9) x+1/1+1/2x=1/2

   ⇒3/2x=-1/2

   ⇒x=-1/3

   BẠN THAM KHẢO NHA

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2. Đang nghĩ câu $10)$ .

   $1) 3x+5=2x-4$

   $⇔ 5+4= 2x-3x$

   $⇔ -x = 9$

   $⇔ x = -9$

      Vậy $x=-9$

   $2) x-7-(2x+1)=5$

   $⇔ x-7-2x – 1 =5$

   $⇔ x – 2x = 5+1+7$

   $⇔ -x = 13$

   $⇔ x = -13$

     Vậy $x=-13$

   $3)(2x-7)-(7x+5)=6$

   $⇔ 2x – 7 – 7x – 5 = 6$

   $⇔ 2x – 7x = 6+5+7$

   $⇔ -5x = 18$

   $⇔ x = -18/5$

     Vậy $x = – 18/5$

   $4) (x+3)-(2x+1)=5$

   $⇔ x+3 – 2x – 1 = 5$

   $⇔ x – 2x = 5+1 – 3$

   $⇔ -x = 3$

   $⇔ x = -3$

      Vậy $x=-3$

   $5) $x+2/3-x/2=x$

   $⇔ 2/3 – x/2 = x -x$

   $⇔ 2/3 – x/2 = 0$

   $⇔ x/2 = 2/3$

   $⇔ x = 4/3$

     Vậy $x=4/3$

   $6) x+7/2-x=1/2$

   $⇔ 7/2 = 1/2$ ($KTM$)

      Vậy $x$ $∈$ $∅$.

   $7) (x-5)(x+3)=0$

   $⇒$ \(\left[ \begin{array}{l}x-5=0\\x+3=0\end{array} \right.\) 

   $⇔$ \(\left[ \begin{array}{l}x=5\\x=-3\end{array} \right.\) 

       Vậy $x$ $∈$ {$-3;5$}

   $8) (x-3)(x+2)=0$

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

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

       Vậy $x$ $∈$ {$-2;3$}

   $9)x+1/1+1/2x=1/2$

   $⇔ x + 1 + 1/2x = 1/2$

   $⇔ x+1/2.x = 1/2 – 1$

   $⇔ x/1 + x/2 = -1/2$

   $⇔ 2x/2 + x/2 = -1/2$

   $⇔ 3x = -1$

   $⇔ x = -1/3$

      Vậy $x=-1/3$

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