`a)`
`(3 - x) + 10 = -15`
`⇔3 - x = -15 - 10`
`⇔3 - x =-25`
`⇔x = 3 - ( -25)`
`⇔x = 28`
`b)`
`10-3(x-1)=-5`
`⇔3(x-1) = 10 - (-5)`
`⇔3(x-1) = 15`
`⇔x - 1 =5`
`⇔x = 5 + 1`
`⇔x = 6`
`c)`
`-12-|5-x|=-14`
`⇔|5-x| = -12 - (-14)`
`⇔|5 - x| = 2`
`⇔`\(\left[ \begin{array}{l}5 - x =2\\5 - x = -2\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=3\\x= 7\end{array} \right.\)
