Question

Układy rownan, prosze rozwiazywac metoda podstawiania : 1. [x = 4 -3y [x + y = -6 2. [x - 3y = - 4 [5x - 2y = -7 3. [-2x + y = -8 [4x - 3y=2 [4. -3x - 2y =-2 [2x + 3y= -2 5. [x + 7y = 22 [y+5 x -2 6. [y = 2x -8 [-12x +9y = -6 7. [x + y =3 x [-2y = 6 8. [2x - 3y = -5 [-x + 5y = 6 9. [4x - 2y = 6 [3x + 6y =12 10. [x - y= 5 [3x + 4y= 8 11. [3x - 3y + 3= 0 [x + 1/2y -2= 0 12. [3x - 4y =14 [-2x + 7y = -18 13.[ x + y= 5 x [- y+1 14. [2x + y =14 [5x + 4y = -17 15. [x +2y= 5 [2x = 5y = -17 16. [2x - y = 4 [-x + y = -7

Answer 1

 1. x = 4 -3y 

x+ y = -6

 

x=4-3y

4-3y+y=-6

 

x=4-3y

-2y=-10

 

y=5

x=4-3*5

 

x=-11

y=5

 

2. x - 3y = - 4  

5x - 2y = -7  

 

x=3y-4

5(3y-4)-2y=-7

 

x=3y-4

15y-20-2y=7

 

x=3y-4

13y=27  /:13

 

y=2 1/13

x=3*27/13 -4

 

x=2 3/13

y=2 1/13

 

3. -2x + y = -8

4x - 3y=2

 

y=2x-8

4x-3(2x-8)=2

 

y=2x-8

4x-6x+24=2

 

y=2x-8

-2x=-22  /:(-2)

 

x=11

y=22-8=14

 

4. -3x - 2y =-2

2x + 3y= -2   /:2

 

-3x-2y=-2

x+3/2y=-1

 

x=-1-3/2y

-3(-1-3/2y)-2y=-2

 

x=-1-3/2y

3+6/2y-2y=-2

 

x=-1-3/2y

3y-2y=-2-3

 

x=-1-3/2y

y=-5

 

x=-1-15/2

y=-5

 

x=-8 1/2

x=-5

 

 

5. x + 7y = 22

y+5 x =-2

 

x=22-7y

y+5(22-7y)=-2

 

x=22-7y

y+110-35y=-2

 

x=22-7y

-34y=-112

 

y=3 5/17

x=22 - 7*3 5/17

 

x=22 -23 1/17

y=3 5/17

 

x=1 1/17

y=3 5/17

 

6. y = 2x -8

-12x +9y = -6

 

y=2x-8

-12x+9(2x-8)=-6

 

y=2x-8

-12x+18x-72=-6

 

y=2x-8

6x=66 

 

x=11

y=22-8= 14

 

7. x + y =3

x-2y = 6

 

x=3-y

x-2y=6

 

x=3-y

3-y-2y=6

 

x=3-y

-3y=9

 

y=-3

x=3-(-3)

 

x=6

y=3

 

8. 2x - 3y = -5

-x + 5y = 6  /*(-1)

 

x-5y=-6

2x-3y=-5

 

x=-6+5y

2(-6+5y)-3y=-5

 

x=-6+5y

-12+10y-3y=-5

 

x=-6+5y

7y=7

 

y=1

x=-6+5=-1

 

 

9. 4x - 2y = 6  /:2

3x + 6y =12   /:3

 

2x-y=3

x+2y=4

 

x=4-2y

2(4-2y)-y=3

 

x=4-2y

8-4y-y=3

 

x=4-2y

-5y=-5

 

y=1

x=4-2

 

x=2

y=1

 

 

10. x - y= 5

3x + 4y= 8

 

x=5+y

3(5+y)+4y=8

 

x=5+y

15+3y+4y=8

 

x=5+y

7y=-7

 

y=-1

x=5-1

 

x=4

y=-1

 

11. 3x - 3y + 3= 0  /:3

x + 1/2y -2= 0  /*2

 

x-y+1=0

2x+y-4=0

 

x=y-1

2(y-1)+y-4=0

 

x=y-1

2y-2+y-4=0

 

x=y-1

3y=6

 

y=2

x=2-1

 

x=1

y=2

 

12. 3x - 4y =14

-2x + 7y = -18  /:(-2)

 

x-7/2y=9

3x-4y=14

 

x=9+7/2y

3(9+7/2y)-4y=14

 

x=9+7/2y

27+10 1/2y-4y=14

 

x=9+7/2y

6 1/2y= -13

 

y=-2

x=9+ 7/2*2

 

x=16

y=-2

 

 

13. x + y= 5

x =- y+1

 

x=-y+1

-y+1+y=5

 

x=-y+1

0=5 równanie sprzeczne (ale sprawdź czy dobrze przepisałeś układ z kasiążki)

 

14. 2x + y =14  /:2

5x + 4y = -17

 

x+1/2y=7

5x+4y=-17

 

x=7-1/2y

5(7-1/2y)+4y=-17

 

x=7-1/2y

35-5/2y+4y=-17

 

x=7- 1/2y

1,5y=-52

 

y=34 2/3

x=7- 17 1/3

 

x=10 1/3

y=34 2/3

 

15. x +2y= 5

2x - 5y = -17

 

x=5-2y

2(5-2y)-5y=-17

 

x=5-2y

10-4y-5y=-17

 

x=5-2y

-9y=-27

 

y=3

x=5-6

 

x=-1

y=3

 

16. 2x - y = 4

-x + y = -7  /*(-1)

 

x-y=7

2x-y=4

 

x=7+y

2(7+y)-y=4

 

x=7+y

14+2y-y=4

 

x=7+y

y=-10

 

x=-3

y=-10

 

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