Question

Rozwiąż układ równań metodą dodawania stronami.

Answer 1

b)

4x - 7y = 3    / * 2

3x + 14y = 5

 

8x - 14y = 6

3x + 14y = 5

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11x = 11

x = 1

 

3x + 14y = 5

3 + 14y = 5

14y = 5 - 3

14y = 2

y = 2/14

y = 1/7

 

x = 1

y = 1/7

 

c)

12x - 5y = -19    / * 2

6x + 10y = -22

 

24x - 10y = -38

6x + 10y = -22

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30x = -60

x = -2

 

6x + 10y = -22

-12 + 10y = -22

10y = -22 + 12

10y = -10

y = -1

 

x = -2

y = -1

 

d)

10x + 21y = -9

-5x - 7y = 8    / * 2

 

10x + 21y = -9

-10x - 14y = 16

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7y = 7

y = 1

 

10x + 21y = -9

10x + 21 = -9

10x = -9 - 21

10x = -30

x = -3

 

x = -3

y = 1