$#Đáp án + Giải thích các bước giải:$
`a)`
`x/7 - 1/7 = 20/35`
`→x/7 - 1/7 = 4/7`
`→x/7 = 4/7 + 1/7`
`→x/7 = 5/7`
`↔x . 7 = 7 . 5 `
`↔x = 5`
Vậy `x=5`
`b)`
`|x - 2|+ 5 = 10`
`→| x - 2 |=10 - 5`
`→| x - 2 |=5`
`→`\(\left[ \begin{array}{l}x-2=5\\x-2=-5\end{array} \right.\)
`→`\(\left[ \begin{array}{l}x=3\\x=-7\end{array} \right.\)
Vậy `x∈{3;-7}`
`c)`
`|x - 2|= 2021^0`
`→|x - 2|= 1`
`→`\(\left[ \begin{array}{l}x-2=1\\x-2=-1\end{array} \right.\)
`→`\(\left[ \begin{array}{l}x=3\\x=1\end{array} \right.\)
Vậy `x∈{3;1}`
$#Cam$
