Giải giúp em, Xin cảm ơn a | 2x – 3 | – | 5 | = | -11 | – 3 b | x | + | y | = 0 c) | x – 3 | + | y + 2 | = 0 d) x.(x + 7) =

$a) |2x-3| – |5| = |-11| – 3$

$⇔ |2x-3| – 5 = 11 – 3$

$⇔ |2x-3| = 13$

$⇒$ \(\left[ \begin{array}{l}2x-3=13\\2x-3=-13\end{array} \right.\) 

$⇔$ \(\left[ \begin{array}{l}x=8\\x=-5\end{array} \right.\)  

  Vậy $x$ $∈$ `{8;-5}`

$b) | x | + | y | = 0$

 Vì : $|x|;|y|$ $≥$ $0$ $∀$ $x$

$⇒$ $\left \{ {{x=0} \atop {y=0}} \right.$ 

    Vậy `(x;y)=(0;0)`

$c) | x – 3 | + | y + 2 | = 0$

 Vì : $|x-3|;|y+2|$ $≥$ $0$ $∀$ $x$

$⇒$ $\left \{ {{x-3=0} \atop {y+2=0}} \right.$ 

$⇔$ $\left \{ {{x=3} \atop {y=-2}} \right.$ 

    Vậy `(x;y)=(3;-2)`

$d) x.(x + 7) = 0$

$⇒$ \(\left[ \begin{array}{l}x=0\\x=-7\end{array} \right.\)

   Vậy $x$ $∈$ `{0;-7}`

$e)(x + 12).(x-3) = 0 $

$⇒$ \(\left[ \begin{array}{l}x=-12\\x=3\end{array} \right.\) 

    Vậy $x$ $∈$ `{-12;3}`

$f)(-x + 5).(3 – x ) = 0$

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

   Vậy $x$ $∈$ `{5;3}`

$g) x.(2 + x).( 7 – x) = 0  $

$⇒$ \(\left[ \begin{array}{l}x=0\\x=-2\\x=7\end{array} \right.\) 

    Vậy $x$ $∈$ `{0;-2;7}`

$ h) (x – 1).(x +2).(-x -3) = 0$

$⇒$ \(\left[ \begin{array}{l}x=1\\x=-2\\x=-3\end{array} \right.\) 

    Vậy $x$ $∈$ `{1;-2;-3}`