11. x+1|3
x+1€D3
x+1€{-3,-1,1,3}
x€{-4,-2,0,2}
12. 3^x=2017^x
=》x=0 solutie unica
3⁰=2017⁰=1
13. a) a+a+1=-11
2a=-12
a=-6
numerele sunt -6 si -5
b) -3×a=a-24
-4a=-24
a=6
14. |x|<4
-4<x<4
A={-3,-2,-1,0,1,2,3}
-x+2>-5
-x>-7
x<7
B=(-infinit, 7) intersectat cu Z*
A/B=multimea vida
AnB={-3,-2,-1,0,1,2,3}