Respostas

2014-03-22T12:09:16-03:00
A U B = 25
A - B = 18 - 3 = 15
A inter B = 3
B - A = 25 - 18 = 7

Então , B = 3 + 7 = 10
1 5 1
2014-03-22T12:19:05-03:00
A = {18 elementos}
B = {x - 3}

18 + (x - 3) = 25
18 + x - 3 = 25
x = 25 - 18 + 3
x = 10

Resposta: 10 elementos
1 5 1