Odpowiedzi

2010-04-10T20:47:46+02:00
1.
x+3y-12=0 => x=12-3y
2x-y-3=0 => x=0,5y+1,5
12-3y=0,5y+1,5
11,5=2,5y
y=4,6
x=-1,8

2.
2x-y-5=0 => y=-2x-5
3x=y-6 => y=3x+6
-2x-5=3x+6
-11=5x
x=-2,2
y=12,6

3.

x+4y-14=0 => x=14-4y
3x-y=20 => x=1/3y+20/3
14-4y=1/3y+20/3
22/3=13/3y
y=22/13
x=94/13
2010-04-10T20:50:44+02:00
1.{x+3y-12=0
{2x-y-3=0

x=12-3y
24-6y-y-3=0
7y=21
y=3
x= 3


2.{2x-y-5=0
{3x=y-6

y=-5+2x
3x+5-2x=-6
x=-11
y=-27



{x+4y-14=0
{3x-y=20
y=-20+3x
x-80+12x-14=0
13x=94
x=94/13
y=-20 + 282/13