sa se determine elementele multimilor
A={x apartine N la puterea x / x<=3}
B={x apartine N / 3<=x<7}
C ={x apartine N / x cifra para ,x<=4}
D= {x apartine N /, x=3*n, napartine N*, n<=3 }
E = {x apartine N / 3* <= 27}
F = {x apartine N / x= 2n-1, 4