Question

Rozwiąż układy równań dowolnym sposobem:

1) \left \{ {{y=3} \atop {x+y=7}} \right.

2) \left \{ {{y=2} \atop {x-y=1}} \right.

3) \left \{ {{y-3} \atop {x-2y=8}} \right.

4) \left \{ {{3x+y=12} \atop {x=2}} \right.

5) \left \{ {{x=1} \atop {x+y=3}} \right.

6) \left \{ {{x+y=5} \atop {y=3}} \right.

7) \left \{ {{x=4} \atop {x-y=1}} \right.

8) \left \{ {{2x=4} \atop {2x+y=7}} \right.

9) \left \{ {{x+3y=10} \atop {3y=6}} \right.

10) \left \{ {{3x-y=12} \atop {x=15}} \right.

11) \left \{ {{x+2y=8} \atop {2y=5}} \right.

12) \left \{ {{5x-3y=10} \atop {3y=5}} \right.

13) \left \{ {{x=9} \atop {2x+3y=21}} \right.

Answer 1

1) \left \{ {{y=3} \atop {x+y=7}} \right.
y=3

x+y=7

 

y=3

x+3=7

 

y=3

x=4 

2) \left \{ {{y=2} \atop {x-y=1}} \right.

y=2

x-y=1

y=2

x-2=1

 

y=2

x=3

3) \left \{ {{y=3} \atop {x-2y=8}} \right.
y=3

x-2*3=8

 

y=3

x-6=8

 

y=3

x=14

4) \left \{ {{3x+y=12} \atop {x=2}} \right.
3x+y=12

x=2

 

3*2+y=12

x=2

 

6+y=12

x=2

 

y=6

x=2

5) \left \{ {{x=1} \atop {x+y=3}} \right.
x=1

x+y=3

 

x=1

1+y=3

 

x=1

y=2

 

6) \left \{ {{x+y=5} \atop {y=3}} \right.
x+y=5

y=3

 

x+3=5

y=3

 

x=2

y=3

7) \left \{ {{x=4} \atop {x-y=1}} \right.
x=4

x-y=1

 

x=4

4-y=1

 

x=4

-y=-3

 

x=4

y=3

8) \left \{ {{2x=4} \atop {2x+y=7}} \right.
2x=4

2x+y=7

 

x=2

2*2+y=7

 

x=2

4+y=7

 

x=2

y=3

9) \left \{ {{x+3y=10} \atop {3y=6}} \right.
x+3y=10

3y=6

 

x+3y=10

y=2

 

x+3*2=10

y=2

 

x+6=10

y=2

 

x=4

y=2

10) \left \{ {{3x-y=12} \atop {x=15}} \right.
3x-y=10

x=15

 

3*15-y=10

x=15

 

45-y=10

x=15

 

-y=-35

x=15

 

y=35

x=15

11) \left \{ {{x+2y=8} \atop {2y=5}} \right.
x+2y=8

2y=5

 

x+2y=8

y=2,5

 

x+2*2,5=8

y=2,5

 

x+5=8

y=2,5

 

x=3

y=2,5

12) \left \{ {{5x-3y=10} \atop {3y=5}} \right.
5x-3y=10

3y=5

 

5x-3y=10

y=5/3

 

5x-3*5/3=10

y=5/3

 

5x-5=10

y=5/3

 

5x=15

y=5/3

 

x=3

y=5/3

13) \left \{ {{x=9} \atop {2x+3y=21}} \right. 

x=9

2x+3y=21

 

x=9

2*9+3y=21

 

x=9

18+3y=21

 

x=9

3y=3

 

x=9

y=1

 

licze na naj 

Answer 2

Rozwiązania w załączniku

 w 12) y= 1⅔ , piszę tu gdyż może być niezbyt widoczne