Odpowiedzi

2010-01-05T22:05:12+01:00
1.

{x + 3y=8
{4x+6y=20

{-4x - 12 y = -32
{4x + 6y = 20
-6y= -12
y=2
x=2

2.
{3X+2Y=21
{X+3Y=14

{3X+2Y=21
{-3x -9y = -42
-7y = -21
y=3
x=5

3.
{5X+3Y=20
{2X+4Y= - 20

{10x + 6y = 40
{-10x - 20y = 100
-14y = 140
y = -10
x=10
2010-01-05T22:18:51+01:00
1
{x+3y=8 |*(-2)
{4x+6y=20

{-2x-6y=-16
{4x+6y=20------------------
+___________ |
2x = 4 |2 4*2 + 6y = 20
x = 2 8 + 6y =20 |-8
6y =12 | 6
y = 2
{x=2
{y=2


2
{3X+2Y=21 ----------------------->3x+2*3=21
{X+3Y=14 | *(-3) 3x+6=21 |-6
3x = 15 |/3
{3X+2Y=21 x = 5
{-3X-9Y=-42
+_____________
-7y= -21 | /(-7)
y = 3
{x=5
{y=3


3
{5X+3Y=20 |*2 ------------------>5x +3*(-10)=20
{2X+4Y= - 20 |*(-5) 5x - 30 =20 | +30
5x = 50 |/5
{10X+6Y=40 x = 10
{-10X-20Y= 100
+____________________
-14y = 140 |/(-14)
y = -10

{x=10
{y=-10