Question

Rozwiaz uklad rownan metodą przeciwnych wspolczynników:

a) 4x + 5y = -4

6x + 7y = -6

b) 2x - 11y = 73

3x - 4y = 47

c) -2x + 5y = -10

7x - 4y = 8

d) 9x + 8y = 1

5x - 6y = 11

Answer 1

a)

4x+5y=-4/*3

6x+7y=-6 /*(-2)

 

12x+15y=-12

-12x-14y=12

----------------- +

y=0

 

4x+5y=-4

4x+5*0=-4

4x=-4/:4

x=-1

 

x=-1

y=0

 

b)

2x-11y=73 /*(-3)

3x-4y=47 /*2

 

-6x+33y=-219

6x-8y= 94

------------- +

25y=-125/:25

y=-5

 

2x-11y=73

2x-11*(-5)=73

2x+55=73

2x=73-55

2x=18/:2

x=9

 

x=9

y=-5

 

c)

-2x+5y=-10 /*7

7x-4y=8 /*2

 

-14x+35y=-70

14x-8y=16

---------------- +

27y=-54 /:27

y=-2

 

-2x+5y=-10

-2x+5*(-2)=-10

-2x-10=-10

-2x=0/:(-2)

x=0

 

x=0

y=-2

 

d)

9x+8y=1/*3

5x-6y=11 /*4

 

27x+24y=3

20x-24y=44

---------------- +

47x=47/:47

x=1

 

9x+8y=1

9*1+8y=8

8y=8-9

8y=-1/:8

y=-1/8

 

x=1

y=-1/8

 

 

Answer 2

zadanie zalaczniku