Răspunsuri

2014-09-02T10:15:12+03:00
A+b=27 => a=27-b
2a-3b=4
2(27-b)-3b=4
54-2b-3b=4
-5b=4-54
-5b=-50
b=50:5
b=10

a=27-10
a=17