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2009-12-14T20:49:01+01:00
{2x+9y=-9
{-3x+3y=8| *-3
{2x+9y=-9
{9x-9y=-24
-------------
{11x=-38|:11
{x= -3,8

{2*(-3,8)+9y=-9
{-7,2+9y=-9
{1,8y=-9|:1.8
{y=5


{2x+3y=4| *-4
{8x-5y=-1
{-8x-12y=-16
{8x-5y=-1
------------
{-17y=-17|:-17
{x=1


2x+3y=4
2+3y=4
3y= 4-2
3y=2|;3
y=⅔
1 1 1
2009-12-14T20:55:57+01:00
{2x+9y=-9
{-3x+3y=8

2x=-9-9y
-3x+3y=8

x=-4,5-4,5y
-3(-4,5-4,5y)+3y=8

x=-4,5-4,5y
13,5+13,5y+3y=8

x=-4,5-4,5y
16,5y=-8,5

x=-4,5-4,5y
y=-0,5
------------------
x=-4,5*2,25
x=-2,25
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