Odpowiedzi

2010-03-23T15:09:08+01:00
A)
3x-2y-5 = 0
x+y = 5

3x-2y-5 = 0
x = 5-y

3(5-y) - 2y-5 = 0
x = 5-y

10-5y = 0
x = 5-y

5y = 10 /:5
x = 5-2

y = 2
x = 3

b)
2x - 2y = -3
x - y = 1

2(1+y) - 2y = -3
x = 1+y

2 + 2y - 2y = -3
x = 1+y

2 = -3
- sprzeczność

c)
3x + 2y = 2
1,5x + y = 1 /* (-2)

3x + 2y = 2
-3x - 2y = 1
-sprzeczność

d)
3x + 2y = 5
x - 2y = 3
+ -------------------------
4x = 8 //:4
x = 2
2 -2y = 3

x = 2
-2y = 3-2

x=2
-2y = 1 /:(-2)

x=2
y= - 1/2