Đáp án:
Giải thích các bước giải:
$a) [(x-3)^{2}+7].2=14$
$(x-3)^{2}+7=7$
$(x-3)^{2}=0$
$x-3=0$
$x=3$
`b) 1,5x:(9-6\{13}/{21})=2\{23}/{25}`
`{3x}/2:({189}/{21}-{139}/{21})={73}/{25}`
`{3x}/2:{50}/{21}={73}/{25}`
`{63x}/{100}={73}/{25}`
$63.x.25=73.100$
$1575x=7300$
`x={292}/{63}`
`c) |x-2/5|-1/3=2`
`|x-2/5|=7/3`
\(\left[ \begin{array}{l}x-\frac{2}{5}=\frac{7}{3}\\x-\frac{2}{5}=\frac{-7}{3}\end{array} \right.\)
\(\left[ \begin{array}{l}x=\frac{41}{15}\\x=\frac{-29}{15}\end{array} \right.\)