Odpowiedzi

2010-03-09T19:29:14+01:00
{ -2x + 5y = -10 /* 4
7x - 4y = 8 / *5
{ -8x + 20 y = - 40
35x - 20y = 40
27 x = 0
x= 0

-2x + 5y = -10
-2 * 0 + 5y = -10
5y = -10
y = -2

-2 *0 + 5 * (-2) = -10
2010-03-09T19:44:51+01:00
METODĄ PODSTAWIANIA.

[ -2x+5y= -10
[7x-4y= 8

[-2x= -10-5y
[7x-4y= 8

[-2x= -10-5y/:(-2)
[7x-4y= 8

[x= 5-5/2y
[7x-4y= 8

[x= 5-5/2y
[7( 5-5/2y)-4y= 8

[x= 5-5/2y
[35-35/2y-4y=8

[x= 5-5/2y
[-13,5y=-27/:(-13.5)

[x= 5-5/2y
[y=2

[x=5-5/2*2
[y=2

[x=0
[y=2
METODA PRZECIWNYCH WSPÓLCZYNNIKÓW.

[ -2x+5y= -10/*7
[7x-4y= 8 /*2

[-14x+35y=-70
[14x-8y=16

35y-8y=-70+16
27y=-54/:27
y=-2

[y=-2
[7x-4y= 8

[y=-2
[7x-4*(-2)=8

[y=-2
[7x+8=8

[y=-2
[7x=8-8

[y=-2
[7x=0/:7

[y=-2
[x=0




PROSZĘ! ;)
2010-03-09T19:48:09+01:00
{-2x+5y=-10 | razy 3,5
{7x-4y=8

{-7x+17.5y=-35
+{ 7x-4y=8
_______________
17,5y-4y=-35+8
13,5y=-27 |: 13,5
y=-2

-2x+5*(-2)=-10
-2x=-10+10
-2x=0 | :-2
x=0

{x=0
{y=-2

Układ sprzeczny.