Odpowiedzi

2009-12-16T16:50:12+01:00
X+y=20
x-y=16

x=36

x-y=16
36-y=16
-y=36-16
-y=20 *(-1)

y=-20
x=36
2009-12-16T16:52:23+01:00
X+y=40/2
x-y=40/2,5

x+y=20
x-y=16 | *(-1)


x+y=20
-x+y=-16

2y=4
y=2

y=2
x+y=20

y=2
x+2=20


y=2
x=20-2


y=2
x=18