Odpowiedzi

2009-12-12T22:23:56+01:00
20/y - 12/x = 1 /:-4
10/y + 8/x = 4 /:2
-(5/y)+3/x= -0,25
5/y + 4/x= 4

4/x+3/x=4-0,25
7/x= 3,75 /*x
7= 3,75x /:3,5
x=2

5/y + 4/x=4
5/y+ 4/2=4
5/y+2=4 /-2
5/y=2 /*y
5=2y /:2
y= 2,5

x=2
y=2,5
3 2 3
2009-12-12T23:18:22+01:00
20/y - 12/x = 1 /*xy
10/y + 8/x = 4 /*xy

20x-12y=xy
10x+8y=4xy /*(-2)

20x-12y= xy
-20x-16y=-8xy
---------------- dodaj
-28y=-7xy /: -y
28=7x
x=4

20/y - 12/x = 1
20/y - 12/4 = 1
20/y - 3 = 1
20/y = 1 +3
20/y =4
20=4y
y=5
4 5 4