Question

Rozwiąż Równania Metodą Podstawiania:

a) {y-x=4

{3(x+y)=24

b) {3x-1=y-2
{4x-3=-2(y-2)

Answer 1

a {y=4+x                                b)   { y=-2+1-3x

    { 3x+3y=72                               { 4x-3=-2y+4

 

    3x+3(4+x)=72                           4x-3=-2(-2+1-3x)+4

    3x+12+3x=72                              4x-3=4-2+6x+4

     6x=72-12

      6x=60| :6                                 4x-6x=4-2+3+4

      x=10

     y=4+10                                        -2x=9| : (-2)

     y=14

    {x=10                                            x=-4,5

     {y=14                                             y=-2+1-3*(-4,5)

                                                            y=-2+1+13,5

                                                        y=12,5

                                                        {x=-4,5

                                                           {y=12,5

Answer 2

a)

{y-x=4

{3(x+y)=24

 

{y=4+x

{3x+3y=24

 

3x+3(4+x)=24

3x+12+3x=24

6x=24-12

6x=12   /:6

x=2

 

y-2=4

y=4+2

y=6

 

b)

{3x-1=y-2

{4x-3=-2(y-2)

 

{-y=-2+1-3x

{4x-3=-2y+4

 

{-y=-1-3x   /*(-1)

{4x-3=-2y+4

 

y=1+3x

4x-3=-2(1+3x)+4

4x-3=-2-6x+4

4x+6x=-2+4+3

10x=5   /:10

x=5/10

x=1/2

 

y=1+3*1/2

y=1+1i1/2

y=2i1/2