x+4=2x+5 |3x+1|=|4|

2 bình luận về “x+4=2x+5 |3x+1|=|4|”

1. a)x+4=2x+5

   =>x-2x=5-4

   =>-x=1

   =>x=-1

   b)|3x+1|=|4|

   =>|3x+1|=4

   => \(\left[ \begin{array}{l}3x+1=-4\\3x+1=4\end{array} \right.\)=>\(\left[ \begin{array}{l}3x=-5\\3x=3\end{array} \right.\) 

   => \(\left[ \begin{array}{l}x=-\dfrac{5}{3}\\x=1\end{array} \right.\) 

   =>x in {-5/3;1}

   Trả lời
2. a) x+4=2x+5

   => x-2x=5-4

   => -x=1

   => x=-1

   Vậy x=-1

   b) |3x+1|=|4|

   => \(\left[ \begin{array}{l}3x+1=4\\-3x-1=4\end{array} \right.\) 

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

   => \(\left[ \begin{array}{l}x=1\\x=-5/3\end{array} \right.\) 

   Vậy x in {1;-5/3}

    

   Trả lời