Question

Matematyka z plusem 2

zad 1 str 99

A)

x=y

5x-y=4

B)

y=2x=1

4x+y=13

c)

5y-x=3

x=3-y

Answer 1

A)

x=y 
5x-y=4

x-y=0 //*(-1)

5x-y=4

-x+y=0

5x-y=4

4x=4

x=1

1-y=0

y=1

B)

y+2x=1 //*(-1)
4x+y=13

-y-2x=-1

4x+y=13

2x=12
x=6

4*6+y=13
y=-11



c)

5y-x=3
x=3-y 

5y-x=3
x+y=3

6y=6
y=1

x+1=3
x=2

Answer 2

a)

x = y

5x - y = 4

podstawiam x za y

 

5x - x = 4

4x = 4

x = 1

 

x = y = 1

 

y - 2x = 1 => y = 2x + 1

4x + y = 13

podstawiam y

4x + 2x + 1 = 13

6x = 12

x = 2

 

y = 2x + 1

y = 2 x 2 +1 = 5

 

x = 2

y = 5

 

c)

5y-x = 3

x = 3-y

podstawiam x

5y -(3-y) = 3

5y -3 +y = 3

6y = 6

y = 1

 

x = 3-y

x = 3-1 = 2

 

x = 2

y = 1

 

 

 

 

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