\(\text{a) 17-(20-x)=-5}\)
⇔ \(20-x=17-\left(-5\right)\)
⇔ \(20-x=22\)
⇔ \(x=20-22\)
⇔ \(x=-2\)
b) \(\text{18-x= -9 . | − 2 | -2}\)
⇔ \(18-x=-9.2-2\)
⇔ \(18-x=-20\)
⇔ \(x=18-\left(-20\right)\)
⇔ \(x=38\)
\(\text{c) 5- | x | =3 }\)
⇔ | x | = 5 - 3
⇔ | x | = 2
⇔ x = 2