Question

Prosze o rozwiazanie rownan dodanych w zalaczniku ;)

Answer 1

a)

x-y=2

1/2x-1=1/4y |*4

 

x-y=2

2x-4=y

x-(2x-4)=2

x-2x+4=2

-x=-2

x=2

 

2-y=2

y=0

 

b)

-x-y=2

2(3x+y)=-20

 

x=-2-y

6x+2y=-20

 

6(-2-y)+2y=-20

-12-6y+2y=-20

-4y=-8

y=2

 

x=-2-2

x=-4

 

c)
4x+3y=54

1/3x=4(1+1/8y)

 

4x+3y=54

1/3x=4+1/2y |*6

 

4x+3y=54

2x=24+3y

 

4x+3y=54

2x-3y=24

------------

6x=78

x=13

 

4*13+3y=54

52+3y=54

3y=2

y=2/3

 

 

 

Answer 2

a)

x – y = 2

1/2x – 1 = 1/4y    /*4

 

x = 2 + y

2x – 4 =y

 

x = 2 + y

2(2+y) – 4 = y

 

x = 2 + y

4 + 2y -4 = y

 

x = 2 + y

2y – y = 0

 

y = 0

x = 2 + 0

 

y = 0

x = 2

 

b)

-x-y = 2

2(3x + y) = -20

 

-x = 2 + y   / *(-1)

6x + 2y = -20

 

x = -2 –y

6 (-2 –y) + 2y = -20

 

x = -2 –y

-12 -6y + 2y = -20

 

x = -2 –y

-4y = -20+12

 

x = -2 –y

-4y = -8   /: (-4)

 

y = 2

x = -2 –2

 

y = 2

x = -4

 

 

c)

4x + 3y = 54

1/3x = 4( 1+ 1/8y)     /*3

 

4x + 3y = 54

x = 12( 1 + 1/8y)

 

4x + 3y = 54

x = 12 + 12/8y    

 

x = 12 + 12/8y    

4(12 + 12/8y)  + 3y = 54

 

x= 12 + 12/8y    

48 + 12/8 *4+  3y = 54

 

x= 12 + 12/8y    

48 + 6y + 3y = 54

 

x= 12 + 12/8y    

9y = 54 – 48

 

x= 12 + 12/8y    

9y = 6     /:9

 

x= 12 + 12/8y    

y = 6/9

 

y = 2/3

x = 12 + 12/8 * 2/3

 

y = 2/3

x = 12 + 1

 

y = 2/3

x = 13