A={11;12;...;28;29}
A={x∈N|10<x<30}
a) C1
A = { 11 ; 12 ; 13; 14;15;16;17;18;19;20;...;29 }
C2
A = { x€N| 10 < x < 30 }
\(A=\left\{11;12;13;14;15;16.....;29\right\}\)
\(A=\left\{x\in N|10< x< 30\right\}\)
A = {11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29}
A= { x | x là số tự nhiên, 10 < x < 30}