Question

1.Rozwiaz uklad rownan metoda

a)podstawiania

{3x+y=9

{2x-5y=-11

b)przeciwnych wspolczynnikow

{3x+4y=2

{5x+7y=1

2.rozwiaz dowolna metoda uklady:

a)

{3(x-y)+4x=8

{3(x-5y)=5-9y

b

{trzy piate x + jedna druga y =2

{jedna druga (2x-y)=2

Answer 1

1

a)

{3x+y=9

{2x-5y=-11

 

{y=9-3x
{2x-5(9-3x)=-11

 

{y=9-3x
{2x-45+15x=-11

 

{y=9-3x

{17x=34

 

{y=9-3x

{x=2

 

{x=2

{y=3

 

b)

{3x+4y=2/*(-5)

{5x+7y=1/*3

 

{-15x-20y=-10

{15x+21y=3

 

y=-7

x=10

 

2

a)

{3(x-y)+4x=8

{3(x-5y)=5-9y

 

{3x-3y+4x=8

{3x-15y=5-9y

 

{3x-3y+4x=8

{3x-15y+9y=5

 

{7x-3y=8/*(-2)

{3x-6y=5

 

{-14x+6y=-16

{3x-6y=5

 

-11x=-11

{x=1

{y=-1/3

 

b)

{3/5x + 1/2y=2/*10

{1/2(2x-y)=2

 

{6x+5y=20

{x-1/2y=2/*10

 

{6x+5y=20

{10x-5y=20

 

16x=40

{x=2,5

{y=3,25