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a+b=9 b+c=16
5a+10b+5c

REPEDE!!!!!!!!





Răspuns :

a=9-b
b=16-c
c=16-b
5(9-b)+10(16-c)+5(16-b)=45-5b+160-10c+80-5b=45-5b+160-10c+80-5b=45-10b+160-10c+80=285-10b-10c=285-10b-10c=285-10(16-c)-10=285-160+10c-10c=285-160=125