Odpowiedzi

2010-02-21T15:58:39+01:00
C).
{x- 2y + 6 = 0 x - 4 + 6 = 0
{4x + 7y - 6 = 0 x + 2 = 0
x = -2
{x-2y = -6 / . (-4)
{4x + 7y = 6

-4x + 8y = 24
4x + 7y = 6
__________
15y = 30 / :15
y = 2


d).
{2(x-3)-y=4
{3(y+2)+2x=0

{ 2x - 6 - y = 4 2x - 6 - 4 = 10
{ 3y + 6 + 2x = 0 2x = 0
x = 0
{ 2x - y = 10 / .(-1)
{ 2x + 3y = -6

{-2x + y = -10
{ 2x + 3y = -6
____________
4y = -16 /: 4
y = -4


{x:2+y=4 5:2 + y =4
{x-y:3=1 y = 1.25

{x + y = 8
{x - y = 3
_________
2x = 11
x = 5.5


f)
{x+2/2 -y=3
{x-y-1/2=1

{x + 1 - y = 3
{x - y - 0.5 = 1

{ x - y = 2
{x - y = 1.5 układ sprzeczny, nie ma rozwiązania

:)
2010-02-21T16:05:44+01:00
C)
{x-2y+6=0
+{4x+7y-6=0
___________
5x+5y=0
x=-5y

5y-2y+6=0
3y+6=0

{y=-2
{x=10
d)
{2(x-3)-y=4
{3(y+2)+2x=0

{2x-6-y=4
+{3y+6+2x=0
___________
4x+2y=4
x=1-1/2y

1-1/2y-6-y=4
{ y=6
{ x= -2