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2010-02-15T13:48:28+01:00
2x-y=4
x-y=7//-1


2x-y=4
-x+y=-7

_________________
x=3
2x-y=4

x=3
6-y=4

x=3
-y=-6+4

x=3
-y=2/-1

x=3
y=-2



2x+5y=9/*3
-3x+4y=-2/*2


6x+15y=27
-6x+8y=-4

__________________-
23y=23

y=1
6x+15y=27

y=1
6x+15=27

y=1
6x=-15+27

y=1
6x=12//6

y=1
x=2


mam nadzieje ze pomoglam pozdrawiam. ;)






2010-02-15T13:50:52+01:00
2x-y=4
x-y=7

metoda podstawiania:
2x-y=4
x=y+7

2(y+7)-y=4
x=y+7

2y+14-y=4
x=y+7

y=4-14
x=y+7

y=-10
x=-10+7

x=-3
y=-10

DRUGI UKŁAD, ta sama metoda:
2x+5y=9
-3x+4y=-2

2x=9-5y
-3x+4y=-2

x=4.5-2.5y
-3x+4y=-2

x=4.5-2.5y
-3(4.5-2.5y)+4y=-2

x=4.5-2.5y
-13.5+7.5y+4y=-2

x=4.5-2.5y
11.5y=-2+13.5 => y=1

x=4.5-2.5*1
x=2

x=2
y=1
2010-02-15T14:00:06+01:00
2x-y=4 2x+5y=9 / : 2
x-y=7 -3x+4y=-2

2x-y=4
x=4+y

x=4+y
2(4+y)-y=4

x=4+y
8+2y-y=4

x=4+y
2y-y=4-8

x=4+y
y=-4

y=-4
x=4+(-4)

y=-4
x=0
______________________

2x+5y=9 / : 2
-3x+4y=-2

x+2.5y=4.5
-3x+4y=-2

x=4.5-2.5y
-3 (4.5-2.5y)+4y=-2

x=4.5-2.5y
-13.5-7.5y+4y=-2

x=4.5-2.5y
-7.5y+4y=-2+13.5

x=4.5-2.5y
-3.5y=11.5/:-3.5

x=4.5-2.5y
y=-3.2

y=-3.2
x=4.5-2.5*(-3.2)

y=-3.2
x=-3.5