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Ma puteti ajuta si pe mine putin la mate? 
 Calculati:
S= 2+4+6+8+ .....+200
S=1+2+3+4+.....+99
Multumesc anticipat!


Răspuns :

1)S=2(1+2+3+.....+100)=

=2*(1+100)*100/2=

=(1+100)*100=

=101*100= 10100

2)S=(1+2+3+...+99)=

=(1+99)*99/2=

=100*99/2=

=50*99=  4950