Răspuns :
A)10<3^x<sau =81 rezulta 10<3^3<sau =81;10<27<sau=81 ;(27=3 la puterea3,3x3x3=27)
10<3^4<sau=81;10<81<sau=81
deci elementele multimii A={3,4}
Brezulta16<sau=4^2<=625;16<=16<=625....
A={x€N l 10<3 la puterea x ≤ 81}
A={3,4}
B ={x |x€N,16 ≤ x ²≤625}
B={4,5,6,....,25}
C={x= ABC| 80< x< 600}
C={100,101,102,......,599}
D={x€N|x=7•k+1,k€N,k ≤7 }
D={1,8,15,22,29,36,43,50}