Odpowiedzi

2010-03-11T22:42:55+01:00
(x+y)/2=15 |*2
(x-2+2y)/2=10 |*2

x+y=30
x-2+2y=20

x=30-y
x+2y=22

30-y+2y=22
-y+2y=22-30
y=-8

x+(-8)=30
x=30+8
x=38


2010-03-11T22:45:46+01:00
Liczby: x, y
(x+y)/2=15
(x-2+2y)/2=10

x+y=30
x-2+2y=20

x+y=30
x+2y=22

x=30-y
30-y+2y=22
30+y=22
y=-8
x=38
2010-03-11T22:57:18+01:00
(a+b):2=15/*2
((a-2)+(b*2)):2=10/*2

a+b=30
a-2+2b=20

a=30-b
a+2b=22

a=30-b
30-b+2b=22

a=30-b
b=22-30

a=30-b
b=-8

a=30-(-8)
b=-8

a=30+8
b=-8

a=38
b=-8

Pozdrawiam ;)