Odpowiedzi

2009-12-06T13:35:07+01:00
A.
4x-2y+3x+9y=42
{
5x+13y-16x+8y=-32

7x+11y=42
{
-11x+21y=-32

7x=42-11y /÷ 7
{
-11x+21y=-32

x=6-1 4/7y
{
-11(6-1 4/7y)+21y=-32

x=6-1 4/7y
{
-66+17 2/7y+21y=-32

x=6-1 4/7y
{
-66+38 2/7y=-32

x=6-1 4/7y
{
38 2/7y=-32+66

x=6-1 4/7y
{
38 2/7y=34 / ÷38 2/7

x=6-1 4/7y
{
y= 17/19

x=6-1 4/7(17/19)
{
y= 17/19

x=6-1 54/133
{
y=17/19

x=4 79/133
{
y=17/19

B.10(y+2)+3(x-5)=x-5
{
25(y+2)+3(x-5)=-10

10y+20+3x-15=x-5
{
25y+50+3x-15=-10

10y+2x=-10 / * 3
{
25y+3x=-45 / * -2

30y+6x=-30
{
-50y-6x=90
_____________________+
30y-50y=-30+90
-20y=60 / ÷ -20
y=-3

y=-3
{
10y+2x=-10

y=-3
{
10*(-3)+2x=-10

y=-3
{
-30+2x=-10

y=-3
{
2x=20 / ÷ 2

y=-3
{
x=10
2009-12-06T13:40:12+01:00
A)

2x-2y+3x+9y=42
{
5x+15y-16x+8y+-32

5x+7y=42
{
-11x+23y=-32

5x=42-7y /:5
{
-11x+23y=-32

x=(42-7y)/5
{
-11((42-7y)/5)+23y=-32/*5

x=(42-7y)/5
{
-55(42-7y)+115y=-32

x=(42-7y)/5
{
-2310+385y+115y=-32

x=(42-7y)/5
{
500y=2278/:500

x=(42-7y)/5
{
y=4 139/250

5x+7(4 139/250)=42
5x+7(1139/250)=42
5x+7973/250=42
5x=42-7973/250
5x=(5/250)-(7973/250)
5x=-7968/250

x=6 234/625
y=4 139/250

zrobiłem tylko jeden przykład bo nie wiem czy to dobrze mi wychodzi bo takie liczby wielkie ale niby nie widze błędu;/