👤

Se stie ca:a+2b+c=51 si 2a+b+2c=42.Aflato a+b+c

Răspuns :

a+2b+c=51 2a+b+2c=42 Adunam cele doua ecuații astfel a+2a+2b+b+c+2c=51+42 3a+3b+3c=93 3(a+b+c)=93 a+b+c=93:3=31
a+2b+c=51
2a+b+2c=42
le adunam
3a+3b+3c=51+42=93
3(a+b+c)=93
a+b+c
=93:3=31