Question

rozwiąż układy równań meodą podstawiania:

1.{3x+2y=19

{5x-y=10

2. {3x-y=7

{2x+3y=1

3. {0,4x+y=6

{x+0,75y=8

4.{2x=1-3y

{1/2x=2-y

5.{x-y-3=0

{2x+3y-11=0

6.{-3(x+2)+2(x+y)=2

{2(y+2)+3(x-y)=2x-1

7.{x-y=-2

{2x-y=1

8.{3x+2y=2

{2x-y=1

9.{5x+4y=4

{7x+5y=6

z góry dziękuje ! :*

Answer 1

1.{3x+2y=19

   {5x-y=10

-y=10-5x/*(-1)

y=-10+5x

3x+2y=19

3x+2(-10+5x)=19

3x-20+10x=19

13x=19+20

13x=39/13

x=3

y=-10+5x

y=-10+5*3

y=-10+15

y=5

x=3

spr

5x-y=10

5*3-5=10

15-5=10

10=10

 

2. {3x-y=7

    {2x+3y=1

-y=7-3x/*(-1)

y=-7+3x

2x+3y=1

2x+3*(-7+3x)=1

2x-21+9x=1

11x=1+21

11x=22/11

x=2

y=-7+3y

y=-7+3*2

y=-7+6

y=-1

spr 3x-y=7

3*2-(-1)=7

6+1=7

7=7

3. {0,4x+y=6

    {x+0,75y=8

y=6-0.4x

x+0.75y=8

x+0.75(6-0.4x)=8

x+4.5-0.3x=8

-0.7x=8-4.5

-0.7x=3.5/(-0.7)

x=-5

y=6-0.4x

y=6-0.4*(-5)

y=6+2

y=8

x=-5

spr.0,4x+y=6

0.4*(-5)+8=6

-2+8=6

6=6

4.{2x=1-3y

   {1/2x=2-y

2x+3y=1

1/2x+y=2

y=2-1/2x

2x+3y=1

2x+3*(2-1/2x)=1

2x+6-3/2x=1

2x-1 1/2x=1-6

1/2x=-5:1/2

x=-10

y=2-1/2*-10

y=2+5

y=7

x=-10

spr.2x+3y=1

2*-10+3*7=1

-20+21=1

1=1

5.{x-y-3=0

   {2x+3y-11=0

x-y=3

2x+3y=11

x=3+y

2x+3y=11

2*(3+y)+3y=11

6+2y+3y=11

5y=11-6

5y=5/5

y=1

x=3+y

x=3+1

x=4

y=1

spr.2x+3y=11

2*4+3*1=11

8+3=11

11=11

6.{-3(x+2)+2(x+y)=2

   {2(y+2)+3(x-y)=2x-1

-3x-6+2x+2y=2

2y+4+3x-3y=2x-1

-x+2y-6=2

-y+3x+4=2x-1

-x+2y=2+6

-y+3x-2x=-1-4

-x+2y=8

-y+x=-5

x=-5+y

-x+2y=8

-(-5+y)+2y=8

5-y+2y=8

5+y=8

y=8-5

y=3

x=-5+y

x=-5+3

x=-2

y=3

spr.-y+x=-5

-3+(-2)=-5

-5=-5

7.{x-y=-2

   {2x-y=1

x=-2+y

2x-y=1

2(-2+y)-y=1

-4+2y-y=1

-4+y=1

y=1+4

y=5

x=-2+y

x=-2+5

x=3

y=5

spr.2x-y=1

2*3-5=1

6-5=1

1=1

8.{3x+2y=2

   {2x-y=1

-y=1-2x/*(-1)

y=-1+2x

3x+2y=2

3x+2(-1+2x)=2

3x-2+4x=2

7x=2+2

7x=4/7

x=4/7

y=-1+2x

y=-1+2*4/7

y=-1+8/7

y=1/7

x=4/7

spr.2x-y=1

2*4/7-1/7=1

8/7-1/7=1

7/7=1

1=1

licze na naj