a,
`3x=-15`
` x = - 15 : 3 `
` x = - 5 `
b,
`3 | x |=6`
` |x|= 6 : 3 `
`⇒` \(\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.\)
c,
`5x=-20`
` x= -20 : 5 `
`x = -4`
d,
`5 | x | =20`
` | x | = 20 : 5`
`⇒` \(\left[ \begin{array}{l}x=4\\x=-4\end{array} \right.\)
e,
`14-(40-x)=-27`
` 40 - x = 14 - 27`
`40 -x = - 13 `
` x = 40 - ( - 13 )`
` x = 53 `
f,
`2(5-x)-7(x-2)=-3`
`16x - 2x - 7x + 14 = -3`
`⇒ x = - 17`
g,
` | x-21 | -31=-10`
` | x - 21 | = -10 + 31`
⇒ \(\left[ \begin{array}{l}x - 21 = 21\\x - 21 = - 21\end{array} \right.\)
⇒ \(\left[ \begin{array}{l}x=42\\x= 0\end{array} \right.\)
h,
`5. | x-3 |-15=105`
⇔`5. |x-3 | = 120`
⇔` |x-3 | = 120 : 5`
⇔ \(\left[ \begin{array}{l}x - 3 =24\\x - 3 = -24\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=27\\x=-21\end{array} \right.\)
