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2010-01-11T16:44:47+01:00
A)
{3x+y=5
{2x-y=0

{y=5-3x
{2x-(5-3x)=0

{y=5-3x
{2x-5+3x=0

{y=5-3x
{5x=5 /:5

{y=5-3*1
{x=1

{y=2
{x=1

b)

{2x-y=5
{x+y=4

{2x-(4-x)=5
{y=4-x

{2x-4+x=5
{y=4-x

{3x=9 /:3
{y=4-x

{x=3
{y=4-3

{x=3
{y=1

c)

{-x-y=-6 /*(-1)
{-x+y=2

{x+y=6
{-x+y=2

{x=6-y
{-(6-y)+y=2

{x=6-y
{-6+y+y=2

{x=6-y
{2y=8 /:2

{x=6-4
{y=4

{x=2
{y=4
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2010-01-11T16:53:52+01:00
A) {3x+y=5 / -3x
{2x-y=0

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

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

{y=5-3x
{-x-5=0 <--- przenosimy 5 na drugą stronę więc będzie {-x=5
{x=-5
y=5 - (-15)
y= (-20)

{x = -5
{y= -20

b) {2x-y=5
{x+y=4 / -y

{2x-y=5
{x=4-y

{2*(4-y) -y = 5
{x=4-y

{8-2y-y=5
{x=4-y

{8-3y=5 <----- 8 przenosimy na tą stronę, więc będzie -3
{x=4-y

{-3y=-3
{x=4-y

{y=1
{x=4-1

{y=1
{x=3

c) {-x-y=-6 / * (-1)
{-x+y=2

{x+y=6
{-x+y=2

{x=6-y
{-(6-y)+y=2

{x=6-y
{-6+y+y=2

{x=6-y
{2y=8

{x=6-4
{y=4

{x=2
{y=4




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2010-01-11T16:55:11+01:00
A){3x+y=5
{2x-y=0

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

{y=5-3x
{2x-3x=0+5

{y=5-3x
{-x=5

{y=5-3*(-5)
{x=-5

{y=20
{x=-5

b){2x-y=5
{x+y=4

{2*(4-y)-y=5
{x=4-y

{8-2y-y=5
{x=4-y

{-3y=-3
{x=4-y

{y=3
{x=4-3

{y=3
{x=1

c){-x-y=-6
{-x+y=2

{-x-y=-6
{y=2+x

{-x-(2+x)=-6
{y=2+x

{-x-2-x=-6
{y=2+x

{-2x=-4
{y=2+x

{x=2
{y=2+2

{x=2
{y=4
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