Question

afla suma numerelor a,b si c,stiind ca
2a+b+c=142
a+2b+c=144
a+b+2c=146

Answer 1

a+b+c=?
2a+b+c=142
a+2b+c=144
a+b+2c=146
2a+a+a+b+2b+b+c+c+2c=142+144+146
4a+4b+4c=432
a+b+c=432:4
a+b+c=108

Answer 2

2a+b+c=142;
a+2b+c=144;
a+b+2c=146;
⇒2a+b+c+a+2b+c+a+b+2c=142+144+146
⇒4a+4b+4c=432;
⇒4[a+b+c]=432
⇒a+b+c=108⇒suma numerelor;