Răspuns :
2a+2b=2(a+b)=80
a+b=40 => a=40-b inlocuim in a 2 3a+2b=95 obtinem 3(40-b)+2b=95 120-3b+2b=95 -b=-25 b=25 a=40-25=> a=15
a+b=40 => a=40-b inlocuim in a 2 3a+2b=95 obtinem 3(40-b)+2b=95 120-3b+2b=95 -b=-25 b=25 a=40-25=> a=15
a=15 ;95-80=15; 15×2+2×b=80; 30+2×b=80; 2×b=80-30;
2×b=50. b=50:2. b=25;
2)15×3+25×2=45+50=95