Odpowiedzi

2010-04-13T22:42:17+02:00
{5+x+9-y=12
x=12-5-9+y
{5+(12-5-9+y)=12
x=12-5-9+y
{5+12-5-9-y=12
x=12-5-9+y
{-y=12-5-12+5+9
x=12-5-9+y
{-y=9
x=12-5-9+9
{-y=9/x(-1)
x=7
{y=-9
x=7