Odpowiedzi

2009-12-05T17:12:55+01:00
A)
7x+7y=21
2x+5y=4.5

7x=21-7y
2x+5y=4.5

x=3-y
2(3-y)+5y=4.5

x=3-y
6-2y+5y=4,5

x=3-y
3y=4,5-6

x=3-y
3y=-1.5

x=3-y
y=-0,25

x=3+0.25
y=-0,25

x=3,25
y=-0,25

b)
6x-9y=6
8x+5y=2.3

6x=6+9y
8x+5y=2.3

x=1+1,5y
8(1+1,5y)+5y=2.3

x=1+1,5y
8+12y+5y=2,3

x=1+1,5y
17y=-5,7

x=1+1,5y
y=-0,335

x=1+1,5*(-0,335)
y=-0,335

x=0,4975
y=-0,335