1)
3,(2)+x<=9,(7)
29/9+x<=88/9
9x<=59
x<=59/9 nu aprtine x -> s:{multimea vida }
!cred ca ai scris gresit ex
2)
a41b | 10 <=> a diferit de 0;a:{1,2,..,9} si b=0 ;
3)
a=2+4+6+...+78 |5
s=(a1+an)n/2= (2+78)39/2=80*39/2= 1560 |5 adv.
4)
abb |2 <=> b:{1,2,...,9}
5)
(1+2+3+...+100)+51*101=5050+51*101=515,201
|
s=(1+100)100/2=101*50=5050
a=515,201 ! care nu este patrat perfect(cred ca ai scris gresit ex)