Toán Lớp 7: |x-2/5|+3/4=11/4 -1+|x+4,5|=-6,2 |x-1/5|=-1/2 1/3-|x-1/5|=1/2

Question

Toán Lớp 7:  |x-2/5|+3/4=11/4 -1+|x+4,5|=-6,2 |x-1/5|=-1/2 1/3-|x-1/5|=1/2

dinhcongson · Answer

|x - 2/5| + 3/4 = 11/4   &rArr; |x - 2/5| = 2   &rArr;  ( left[  begin{array}{l}x - 2/5 = 2  x - 2/5 = -2 end{array}  right. )    &rArr;  ( left[  begin{array}{l}x = 12/5  x = -8/5 end{array}  right. )    Vậy  S = {12/5 ; -8/5}   -1 + |x + 4,5| = -6,2   &rArr; |x + 4,5| = -6,2 - (-1) = -5,2   Vậy  S = {&empty;}   |x - 1/5| = -1/2   Vậy  S = {&empty;}   1/3 - |x - 1/5| =1/2   &rArr; |x - 1/5| = -1/6   Vậy  S = {&empty;}

tongtung · Answer

$|x- dfrac{2}{5}|+ dfrac{3}{4}= dfrac{11}{4}$ $|x- dfrac{2}{5}|=2$ $&hArr;x- dfrac{2}{5}=&plusmn;2$ $+,x- dfrac{2}{5}=2$ $x= dfrac{12}{5}$ $+,x- dfrac{2}{5}=-2$ $x= dfrac{-8}{5}$ Vậy x&isin;{ frac{12}{5}; frac{-8}{5}}   ---------------------   $-1+|x+4,5|=-6,2$ $|x+4,5|=-5,2$ (v&ocirc; l&yacute;) $&rArr;$ V&ocirc; nghiệm --------------------- $|x- dfrac{1}{5}|= dfrac{-1}{2}$ (v&ocirc; l&yacute;) $&rArr;$ V&ocirc; nghiệm ---------------------    $ dfrac{1}{3}-|x- dfrac{1}{5}|= dfrac{1}{2}$ $|x- dfrac{1}{5}|= dfrac{-1}{6}$ (v&ocirc; l&yacute;) $&rArr;$ V&ocirc; nghiệm