Question

Pilnee na jutro ...

Prosze o odpowiedz w zalaczniku ...

Answer 1

a)

(2x-y+3)/3  - (x-2y+3)/4 = 4          /*12

(3x-4y+3)/4 + (4x-2y-9)/3 = 4      /*12

 

4(2x-y+3)  - 3(x-2y+3) = 48         

3(3x-4y+3) + 4(4x-2y-9) = 48

 

8x -8y +12 -3x +6y – 9 =48

9x -12y +9 +16x -8y -36 = 48

 

5x -2y =48 -3

-20y +25x = 48 +27

 

5x -2y =45         /*(-5)

-20y +25x = 75

 

 10y  -25x = -225  

-20y +25x = 75

-------------------  dodajemy stronami

-10 y = -150    /: (-10)

y = 15

5x -2y =45

5x -2*15 =45

5x = 45-30

5x = 15  /:5

x=3

y=15

 

b)

1-0,3(y-2) = (x+1)/5           /*10

(y-3)/4 = (4x+9)/20 -1,5    /*20

 

10-3(y-2) = 2(x+1)

5(y-3) = (4x+9) -30

 

10 – 3y+6=2x+2

5y -15 = 4x +9-30

 

-3y -2x = 2 -16

5y -4x = -21 +15

 

-3y -2x = -14     /*(-2)

5y -4x = -6

 

6y+4x = 28    

5y -4x = -6

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

11y = 22  / :11

y =2

5y -4x =-6

5*2 -4x = -6

-4x = -6 -10

-4x = -16   /:  (-4)

 

x = 4

y = 2