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2009-12-10T21:00:28+01:00
{2A +3B=42
{A+B= 18 | - A

2A + 3B = 42
B=18-A

2A+3(18-A)=42
B=18-A

2A+54-3A=42
B=18 - A

-A+54=42 | - 54
B=18-A

-A=-12 | *(-1)
B=18-A

A=12
B=18 - 12

A=12
B=6

____________


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

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

b=4a-2
3a+28a-14=1,5

b=4a-2
31a-14=1,5 |+14

b=4a-2
31a=15,5 |:31

b=4a-2
a=0,5

b=4*0,5-2
a=0,5

b=0
a=0,5
Najlepsza Odpowiedź!
2009-12-10T21:02:07+01:00
Oblicz:
{2A +3B=42
{A+B= 18

{A = 18-B
{2A +3B=42

{A = 18-B
{2*(18-B) +3B = 42

{A = 18-B
{36 -2B +3B = 42

{A = 18-B
{ B = 42-36 = 6

{A = 18-6 = 12
{B = 6

{A = 12
{B = 6

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

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

{b = 4a -2
{3a +28a -14 = 1,5

{b = 4a -2
{31a = 1,5 +14

{b = 4a -2
{a = 15,5 : 31 = 1/2

{b = 4*(1/2) -2 = 2-2 =0
{a = 1/2

{a = 1/2
{b = 0
2009-12-10T21:04:14+01:00
A. {2A +3B=42
{A+B=18

{2A +3B=42
{A=18-B

{2(18-B)+3B=42
{A=18-B

{36-2B+3B=42
{A=18-B

{B=42-36=6
{A=18-6=12

{B=6
{A=12

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

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

{4a-2=b
{3a+28a-14=1,5

{4a-2=b
{31a=15,5

{4a-2=b
{a=15,5/31=0,5

{b=4*0,5-2=0
{a=0,5