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Daca a+2b+ c=51 si 2a+b+2c= 42 aflati a+ b+ c = ?


Răspuns :

a+2b+c=51
2a+b+2c=42
3a+3b+3c=93
3(a+b+c)=93
a+b+c=93/3=31

a+2b+c=51
2a+b+2c=42
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3a+3b+3c=51+42
3*(a+b+c)=93
a+b+c=93/3
⇒a+b+c=31

Sper ca te-am ajutat!