Question

Rozwiąż układy równań:

a) x+2y= 9

4x-2y= -4

b) 3x+y= 1

-3x+y= 13

c) 2x-y= 5

x+3y= -8

d) -2x+y= 6

3x-2y= -9

e) 2x+3y= 18

x+y= 7

Dodatkowe:

1. -2x-y= 6

2x-5y= 6

2. 4x-3y= -26

x+y= -3

3. x+4y= 12

4x+y= 18

4. 3x+y= -6

x+3y= -10

Dziękuje :D

Answer 1

a) x+2y= 9

    4x-2y= -4

 

x=9-2y

4(9-2y)-2y=-4

 

x=9-2y

36-8y-2y=-4

 

x=9-2y

-10y=-40

 

y=4

x=1

 

 

 

b) 3x+y= 1

    -3x+y= 13

 

2y=14/:2

y=7

 

3x+7=1

3x=-6/:3

 

x=-2

y=7

 

 

c) 2x-y= 5

    x+3y= -8

 

x=-8-3y

2(-8-3y)-y=5

 

x=-8-3y

-16-6y-y=5

 

x=-8-3y

-7y=21/:(-7)

 

y=-3

x=-8-3*(-3)

 

y=-3

x=1

 

 

 

d) -2x+y= 6

    3x-2y= -9

 

y=6+2x

3x-2(6+2x)=-9

 

y=6+2x

3x-12-4x=-9

 

y=6+2x

-x=3/*(-1)

 

x=-3

y=4

 

 

e) 2x+3y= 18

     x+y= 7

 

x=7-y

2(7-y)+3y=18

 

x=7-y

14-2y+3y=18

 

x=7-y

y=4

 

x=3

y=4

 

 

1. -2x-y= 6

     2x-5y= 6

 

-6y=12/:(-6)

y=-2

 

2x-5*(-2)=6

2x+10=6

2x=-4/:(2)

x=-2

 

y=-2

x=-2

 

 

 

2. 4x-3y= -26

     x+y= -3

 

y=-3-x

4x-3(-3-x)=-26

 

y=-3-x

4x+9+3x=-26

 

y=-3-x

7x=-35/:7

 

y=-3-x

x=-5

 

y=2

x=-5

 

 

3. x+4y= 12

    4x+y= 18

 

x=12-4y

4(12-4y)+y=18

 

x=12-4y

48-16y+y=18

 

x=12-4y

-15y=-30/:(-15)

 

x=12-4y

y=2

 

x=4

y=2

 

 

4. 3x+y= -6

    x+3y= -10

 

y=-6-3x

x+3(-6-3x)=-10

 

y=-6-3x

x-18-9x=-10

 

y=-6-3x

-8x=8/:(-8)

 

y=-6-3x

x=-1

 

y=-3

x=-1