Răspuns :

Răspuns:

60

Explicație pas cu pas:

3a+6b=42 |:3, ⇒a+2b=14

3b+5a+c=32

7(a+b)+c=???

7(a+b)+c=7a+7b+c=5a+3b+c+2a+4b=32+2·(a+2b)=32+2·14=32+28=60

Răspuns:

3a+6b=42 I :3

3b+5a+c=32

a+2b=14

3b+5a+c+2(a+2b)=32+2·14

3b+5a+c+2a+4b=60=> 7a+7b+c=60=>7(a+b)+c=60