Ответы и объяснения

2013-09-06T20:52:13+04:00
{2(x+y)=(x-y)+5
{3(x+y)=(x-y)+8
x+y=a
x-y=b
{2a=b+5
{3a=b+8
-a=-3
a=3
6=b+5
b=1
{x+y=3
{x-y=1
x=3-y
3-y-y=1
3-2y=1
2y=2
y=1
x=3-1
x=2