Răspunsuri

2014-08-23T12:06:23+03:00
2014-08-23T12:06:57+03:00
A+b=39
a-b=15  (adunam)
2a\=54
a=27
b=39-a=39-27=12

x+y=39
x-y=15
x+y=39
x-y=15
2x=54
x+y=39
x-y=15
2x=54
x=54:2
x=27
27+y=39
y=39-27
y=12