|x-5|=(58+79)+(125-27-29) 7)-|x-6|=-(-63-|-175|+89)-(63+89) 8)|5-x|+15=26-|-30|-(5-30) 9)5-|x-4|=-7+(23-54)-(-54+23) (2 trả lời)

0 bình luận về “|x-5|=(58+79)+(125-27-29) 7)-|x-6|=-(-63-|-175|+89)-(63+89) 8)|5-x|+15=26-|-30|-(5-30) 9)5-|x-4|=-7+(23-54)-(-54+23) (2 trả lời)”

1. $\left | x-5 \right |=(58+79)+(125-27-29)\\\Leftrightarrow \left | x-5 \right |=137+69=206\\\Leftrightarrow \left[ \begin{array}{l}x-5=206\\x-5=-206\end{array} \right.\\\Leftrightarrow \left[ \begin{array}{l}x=211\\x=-201\end{array} \right.$
   Vậy $x\in \left \{ 201;-201 \right \}$
   $7) -|x-6|=-(-63-|-175|+89)-(63+89)\\\Leftrightarrow -|x-6=-(-63-175+89)-152\\\Leftrightarrow -|x-6|=-(-149)-152\\\Leftrightarrow -|x-6|=149-152\\\Leftrightarrow -|x-6|=-3\\\Leftrightarrow |x-6|=3\\\Leftrightarrow \left[ \begin{array}{l}x-6=3\\x-6=-3\end{array} \right.\\\Leftrightarrow \left[ \begin{array}{l}x=9\\x=3\end{array} \right.$
   Vậy $x\in \left \{ 3;9 \right \}$
   $8) |5-x|+15=26-|-30|-(5-30)\\\Leftrightarrow |5-x|+15=26-30-(-25)\\\Leftrightarrow |5-x|+15=26-30+25\\\Leftrightarrow |5-x|+15=21\\\Leftrightarrow |5-x|=21-15\\\Leftrightarrow |5-x|=6\\\Leftrightarrow \left[ \begin{array}{l}5-x=6\\5-x=-6\end{array} \right.\\\Leftrightarrow \left[ \begin{array}{l}x=-1\\x=11\end{array} \right.$
   Vậy $x\in \left \{ -1;11 \right \}$
   $9) 5-|x-4|=-7+(23-54)-(-54+23)\\\Leftrightarrow 5-|x-4|=-7+(-31)-(-31)\\\Leftrightarrow 5-|x-4|=-7-31+31\\\Leftrightarrow 5-|x-4|=-7\\\Leftrightarrow -|x-4|=-7-5=-12\\\Leftrightarrow |x-4|=12\\\Leftrightarrow \left[ \begin{array}{l}x-4=12\\x-4=-12\end{array} \right.\\\Leftrightarrow \left[ \begin{array}{l}x=16\\x=-8\end{array} \right.$
   Vậy $x\in \left \{ -8;16 \right \}$

    

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2. Đáp án:

    Dưới

   Giải thích các bước giải:

    $a) |x-5|=(58+79)+(125-27-29)$

   $⇒|x-5|=206$

   $TH1:x-5=206$

   $⇒x=211$

   $TH2:x-5=-206$

   $⇒x=-201$

   $b) -|x-6|=-(-63-|-175|+89)-(63+89)$

   $⇒-|x-6|=63+175-89-63-89$

   $⇒-|x-6|=-3$

   $⇒|x-6|=3$

   $TH1:x-6=3$

   $⇒x=9$

   $TH2:x-6=-3$

   $⇒x=3$

   $c) |5-x|+15=26-|-30|-(5-30)$

   $⇒|5-x|+15=26-30-5+30$

   $⇒|5-x|+15=21$

   $⇒|5-x|=6$

   $TH1:5-x=6$

   $⇒x=-1$

   $TH2:5-x=-6$

   $⇒x=11$

   $d) 5-|x-4|=-7+(23-54)-(-54+23)$

   $⇒5-|x-4|=-7+23-54+54-23$

   $⇒5-|x-4|=-7$

   $⇒|x-4|=12$

   $TH1:x-4=12$

   $⇒x=16$

   $TH2:x-4=-12$

   $⇒x=-8$

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