👤

stiind ca a+c=20 si c+d=8 aflati 4a+7c+3d

Răspuns :

a+c=20|•4 => 4a+4c=80
c+d=8|•3 => 3c+3d=24
4a+4c+3c+3d=80+24
4a+7c+3d=104