Odpowiedzi

2009-12-16T20:46:56+01:00
1 {2x-y=10
x=17-5

2razy12-y=10
24-y=10
y=14

2x-14=10
2x=22/2
x=12

2 {n=9-3n
2m-5(9-3n)= -11

2m-45+15m= -11
17m=34/17
m=2
n=3

3 {4a-2=b
3a+7b=1,5

{b=4a-2
3a+7b=1,5

3a+7(4a-2)=1,5
31a=15,5/31
a=0,5
b=4razy0,5-2
b=0

4 {5x=4-2(3-4x)
y=3-4x

13x=-2/13
x=-6,5
y=26

5 {6(-9,5-5y)-3y=9
x=-9,5-5y

33y=66/-33
y=-2
x=0,5

2009-12-16T20:48:37+01:00
1.
2x-y=10 | *5
x+5y= -17

10x-5y=50
x=5y=-17

11x=33 | :11

x=3
2x-y=10
2*3-y=10
6-y=10
-y=10-6 | :(-1)
y=-4

2.
3m+n=9 | *5
2m-5n= -11

15m+5n=45
2m-5n=-11

17m=34 | :17
m=2

2m-5n=-11
2*2-5n=-11
4-5n=-11
-5n=-11-4
-5n=-15 | :(-5)
n=3

3.
4a-b=2 | *7
3a+7b=1,5

28a-7b=14
3a+7b=1,5

31a=15,5 | :31
a=0,5

4a-b=2
4*0,5-b=2
2-b=2
-b=2-2 | :(-1=
b=0

4.
5x+2y=4
4x+y=3 | *(-2)

5x+2y+4
-8x-2y=-6

-3x=-2 | :(-3)
x=2/3

4x+y=3
4*2/3+y=3
2i2/3+y=3
y=3-2i2/3
y=1i1/3

5.
6x-2y=9
x+5y=-9,5 | *(-6)

6x-2y=9
-6x-30y=57

-33x=66 | :(-33)
x=-2

6x-3y=9
6*(-2)-3y=9
-12-3y=9
-3y=9+12
-3y=21 | :(-3)
y=-7