|x|<9 => -9<x<9 => x∈(-9,9)
|x-7|<5 => -5<x-7<5 |+7
2<x<13 => x∈(2,13)
|x-8|<0 => x-8=0 (deoarece modulul este mereu pozitiv) => x=8
|2x-13|<13 => -13<2x-13<13 |+13
0<2x<26 |:2
0<x<13 => x∈(0,13)
|15x-10|<20 => -20<15x-10<20 |+10
-10<15x<30 |:15
[tex]-\frac{2}{3} < x < 2[/tex] => x∈([tex]-\frac{2}{3}, 2[/tex])
