Question

Rozwiąż ukłąd równań.

Answer 1

*-razy, mnożenie

a){x=x-y/3+1 /*3

{2=y-x

 

{3x=x-y+3

{x-y=-2

 

{4x+y=3

{x-y=2

5x=5 /:5

x=1

 

{x=1

{1-y=2

 

{x=1

{-y=1

 

{x=1

{y= -1

 

b) {x-5/3 = y+3/5 /*15

{y=4(x+y-1/2)

 

{5x-25=3y+9

{y=4x+4y-2

 

{5x-3y=34

{-4x-3y= -2 /*-1

 

{5x-3y=34

{4x+3y= 2

9x=36 /:9

x=4

 

{x=4

{4*5 -3y=34

 

{x=4

{20-3y=34

 

{x=4

{-3y=14 /:-3

 

{x=4

{y= -14/3

 

{x=4

{y=-4 2/3

 

c) {x- y+2/3=y+ x+1/2 /*6

{8=x+3y

 

{6x-2y-4=y+3x+3

{-x-3y=-8

 

{3x-3y=7

{-x-3y=-8 /*-1

 

{3x-3y=7

{x+3y=8

4x=15 /:4

x=15/4

 

{x=3 ¾

{3 ¾+3y=8

 

{x=3 ¾

{3y=4 ¼ /:3

 

{x=3 ¾

{y=1 ¼

 

d) {x+2/4 =y-1/3 /*12

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

 

{3x+6=4y-4

{25-5x-5y=2x+4y

 

{3x-4y= -10 /*7

{-7x-9y= -25 /*3

 

{21x-28y= -70

{-21x-27y= -75

-55y= -145

y=145/55