`a)|2x-15|=5`
`→` \(\left[ \begin{array}{l}2x-15=5\\2x-15=-5\end{array} \right.\)
`→` \(\left[ \begin{array}{l}2x=20\\2x=10\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=10\\x=5\end{array} \right.\)
Vậy `x∈{10;5}`
`b)51-|4x+1|=34`
`→|4x+1|=51-34`
`→|4x+1|=17`
`→` \(\left[ \begin{array}{l}4x+1=17\\4x+1=-17\end{array} \right.\)
`→` \(\left[ \begin{array}{l}4x=16\\4x=-18\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=4\\x=-4,5\end{array} \right.\)
Vậy `x∈{4;-4,5}`
`c)|7x-9|+52=62`
`→|7x-9|=62-52`
`→|7x-9|=10`
`→` \(\left[ \begin{array}{l}7x-9=10\\7x-9=-10\end{array} \right.\)
`→` \(\left[ \begin{array}{l}7x=19\\7x=-1\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=\dfrac{19}{7}\\x=\dfrac{-1}{7}\end{array} \right.\)
Vậy `x∈{19/7;-1/7}`
