Question

To z równań z dwiema niewiadomymi z 2 gim.

Trzeba Wyznaczyć x i y

1.{-(x+1)-2(y+1)=-5

{3x+5y=7

2.{2(8y-x)-(x-y)=-15

{3(x+y)-4(x-y)=-3

DAJE NAJ :)

Answer 1

1.

-(x+1)-2(y+1)=-5

3x+5y=7

 

-x-1-2y-1=-5

3x+5y=-5

 

-x-2-2y=-5

3x+5y=7

 

-x-2y=-3

3x+5y=7

 

x+2y=3

3x+5y=7

 

x=3-2y

3(3-2y)+5y=7

 

x=3-2y

9-6y+5y=7

 

x=3-2y

9-y=7

 

x=3-2y

-y=-2

 

x=3-2y

y=2

 

x=3-2*2

y=2

 

x=3-4

y=2

 

x=-1

y=2

 

2.

2(8y-x)-(x-y)=-15

3(x+y)-4(x-y)=-3

 

16y-2x-x+y=-15

3x+3y-4x-4x=-3

 

17y-3x=-15

-x-y=-15

 

17y-3x=-15

x+y=15

 

17y-3x=-15

x=15-y

 

17y-3(15-y)=-15

x=15-y

 

17y-45+3y=-15

x=15-y

 

20y-45=-15

x=15-y

 

20y=30

x=15-y

 

y=3/2

x=15-3/2

 

y=3/2 = 1 i 1/2

x=13 i 1/2