Odpowiedzi

2010-04-08T16:29:34+02:00
A)(y+5x-7=0)
(x+2y+5) tu chyba powinno być tak x+2y=5
y+5x-7=0
x+2y=5

y=-5x+7
x+2(-5x+7)=5

y=-5x+7
x-10x+14=5

y=-5x+7
-9x=5-14

y=-5x+7
-9x=-9

y=-5x+7
x=1

y=-5*1+7
x=1

y=-5+7
x=1

y=2
x=1

y+5x-7=0
x+2y=5

2+5*1-7=0
1+2*2=5

0=0
5=5

b)(x+y=8)
(x-y=6)

x=8-y
8-y-y=6

x=8-y
-2y=6-8

x=8-y
-2y=-2

x=8-y
y=1

x=8-1
y=1

x=7
y=1

x+y=8
x-y=6

7+1=8
7-1=6

8=8
6=6