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2010-03-17T15:25:08+01:00
{3x-y=11
{x+2y=6
x=6-2y
3(6-2y)-y=11
18-6y-y=11
-7y=11-18
-7y=-7 /:(-7)
y=7
x= 6-2*7= 6-14 = -8
{x= -8
{y= 7

{3x+2y=18
{x-y=1
x=y+1
3(y+1)+2y=18
3y+3+2y=18
5y=18-3
5y=15/:5
y=3
x=3+1=4
{x= 3
{y = 4

{2x-y=4
{x+y=5
x=5-y
2(5-y)-y=4
10-2y-y=4
-3y=4-10
-3y=-6 /:(-3)
y= 2
x=5-2 =3
{x = 3
{y= 2

{4x+3y= 9
{2x-7y=13
4x=9-3y /:4
x= 9-3y/4
2*9-3y/4-7y=13
9-3y/2 - 7y = 13 /*2
9-3y-14y=26
-17y=26-9
-17y=17 /:(-17)
y = -1
x= 9-3*(-1) / 4 = 9+3 / 4 = 12/4 = 3
{x=3
{y= -1

{0,25x+3y= 7
{0,5x+6y=14
3y=7-0,25x /:3
y= 7-0,25x /3
0,5x+6*7-0,25x/3= 14
0,5x+2(7-0,25x)=14
0,5x+14-0,5x=14
14=14
to równanie nie ma rozwiązania



2010-03-17T15:32:30+01:00
3x-y=11 /*2
x+2y=6
6x-2y=22
x+2y=6
7x=28 /:7
x=4

3x+2y=18
x-y=1/*2
3x+2y=18
2x-2y=2
5x=20/:5
x=4

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

4x+3y=9/*7
2x-7y=13/*3
28x+21y=63
4x-21y=39
32x=102/:32
x=3,6/102

0,25x+3y=7/*(-4)
0,5x+6y=14/*2
x-12y=(-28)
x+12y=28
2x=0/:2
x=0

Proszę ;)