Sejam $\,A\,=\, \lbrace 5\rbrace \,$ e $\,B\,=\, \lbrace 3, 7 \rbrace \,$. Todas as
a)
$\, \lbrace(5; 3) \rbrace \,$,$\, \lbrace (5; 7) \rbrace \,$ e $\, \lbrace(5; 3), (5; 7) \rbrace \,$
b)
$\,\varnothing\,$, $\, \lbrace (5; 3)\rbrace \,$, $\, \lbrace (5; 7)\rbrace \,$ e $\,A\,\times \,B$
c)
$\, \lbrace (5;3) \rbrace \;$ e $\; \lbrace (5; 7)\rbrace \,$
d)
$\,\varnothing\,$, $\,\lbrace \, (3; 5)\,\rbrace\,$, $\,\lbrace \, (7; 5)\,\rbrace\;$ e $\;A\,\times\,B$
e)
$\,\varnothing\,$, $\,\lbrace \, (5; 3)\,\rbrace\;$ e $\;\lbrace \, (5; 7)\,\rbrace\,$
