Question

{2x-11y=73

{3x-4y=47

{-2x+5y=-10

{7x-4y=8

Answer 1

{2x-11y=73 =>x=(73+11y)/2

{3x-4y=47

(219+33y)/2-4y=47

219+33y-8y=94

25y=-125

y=-5

x=(73-55)/2=9

 

{-2x+5y=-10 =>x=(5y+10)/2

{7x-4y=8

35y+70-8y=-20

27y=-90

y=-10/3

x=-10/3

Answer 2

{2x-11y=73   /*-3

{3x-4y=47    /*2

 

{-6x+33y=-219

{6x-8y=94

+

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

25y=-125

y= -5

 

{3x+20=47

{3x=27

x= 9

 

 

{-2x+5y=-10   /*7

{7x-4y=8     /*2

 

{-14x+35y=-70

{14x-8y=16

+

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

27y=-54

y=-2

 

{7x-4y=8  => 7x+8=8

7x=0 /:7

x=0

 

W dwóch przypakdach użyłem Metody przeciwnych sprólczynników a potem podstawiania :)