Tìm x : | x+2 | = 0 | X-5|= |-7| |X-3|=7-( -2) (7-x ) – (25+7) = – 25

0 bình luận về “Tìm x : | x+2 | = 0 | X-5|= |-7| |X-3|=7-( -2) (7-x ) – (25+7) = – 25”

1. | x+2 | = 0

   *TH1:

   x+2 = 0

   x     =  -2 

   *TH2 :

   -x -2=0

   x      = -2

   | X-5|= |-7|

   *TH1 :

   x -5= -7

   x     = -2

   *TH2 :

    -x +5= -7

   x        = 12

   |X-3|=7-( -2)

   *TH1 :

   x -3= -14

   x     = -11

   *TH2 :

   -x +3= -14

   x       = 17

   (7-x ) – (25+7) = – 25

   7-x – 25-7 = -25

   x              = 0

   Bình luận

2. a, | x+2 | = 0

   ⇔ x+2=0

   ⇔ x=-2

   b, | x-5|= |-7|

   ⇔ | x-5|=7

   ⇔ \(\left[ \begin{array}{l}x-5=7\\x-5=-7\end{array} \right.\) 

   ⇔ \(\left[ \begin{array}{l}x=12\\x=-2\end{array} \right.\) 

    c, |x-3|=7-( -2)

   ⇔ |x-3|=9

   ⇔ \(\left[ \begin{array}{l}x-3=9\\x-5=-9\end{array} \right.\)

   ⇔ \(\left[ \begin{array}{l}x=12\\x=-4\end{array} \right.\) 

   d, (7-x ) – (25+7) = – 25

   ⇔ 7-x-25-7=-25

   ⇔ -x-25=-25

   ⇔ x=0

   Bình luận