Răspuns :
Răspuns:
a+b=25
a=25-b
4-(25-b)+7b=115
-25+b+7b=111
8b=136
b=17
a=25-17
a=8
a=8
b=17
a+b=25
4-a+7b=115
a+b=24 => b=25-a
4- a +7(25-a) =115
4-a+7*25-7a=115
-8a+175=115-4
-8a+175=111
-8a=111-175
-8a=-64/(-1)
8a=64=> a=64/8b => a=8
8+b=25 => b=25-8=> b= 17