Question

Rozwiaz uklad metoda podstawiania: a/{3x+y=-3 {-x+3y=11 , b/ {x+y=6 {5x+y=-2, c/ {x-y+2=0 {2y=x+6, d/ {1/2x+y=4 {2x-4y=8 , 1/2 to ulamek Dam naj..

Answer 1

a)

3x+y=-3

-x+3y=11

 

y=-3x-3

-x-9x-9=11

 

y=-3x-3

-10x=20/-10

 

y= 3

x=-2

 

 

b)

x+y=6

5x+y=-2

 

x=6-y

5(6-y)+y=-2

 

x=6-y

30-5y+y=-2

 

x=6-y

-4y=-32/ -4

 

x=6-y

y=8

 

x=-2

y=8

 

 

c)

x-y+2=0

2y=x+6

 

x-y=-2

2y=x+6

 

x=-2+y

2y=-2+y+6

 

x=-2+y

y=4

 

x=2

y=4

 

d)

1/2x+y=4

2x-4y=8

 

y=4-1/2x

2x-4(4-1/2x)=8

 

y=4-1/2x

2x-16+2x=8

 

y=4-1/2x

4x=24/4

 

y=4-1/2x

x=6

 

y=1

x=6

Answer 2

a)

{3x+y=-3

{-x+3y=11

{y=-3x-3

{-x+3y=11

{y=-3x-3

{-x+3(-3x-3)=11

{y=-3x-3

{-x-9x-9=11

{y=-3x-3

{-10x=11+9

{y=-3x-3

{-10x=20/:(-10)

{y=-3x-3

{x=-2

{y=-3*(2)-3

{x=-2

{y=-6-3

{x=-2

{y=-9

 

b)

 {x+y=6

{5x+y=-2

{x=-y+6

{5x+y=-2

{x=-y+6

{5(-y+6)=-2

{x=-y+6

{-5y+30=-2

{x=-y+6

{-5y=-2-30

{x=-y+6

{-5y=-32/:(-5)

{x=-y+6

{y=6,4

{x=-6,4+6

{y=6,4

{x=-0,4

 

c)

{x-y+2=0

{2y=x+6

{x=y-2

{2y=x+6

{x=y-2

{2y=y-2-2

{x=y-2

{2y-y=-4

{x=y-2

{y=-4

{x=-4-2

{y=-4

{x=-6

 

d)

{1/2x+y=4

{2x-4y=8

{y=-1/2x+4

{2x-4y=8

{y=-1/2x+4

{2x-4(-1/2x+4)=8

{y=-1/2x+4

{2x+2x-16=8

{y=-1/2x+4

{4x=8+16

{y=-1/2x+4

{4x=24/:4

{y=-1/2x+4

{x=6

{y=-1/2*6+4

{x=6

{y=-3+4

{x=6

{y=1