Question

Rozwiąz układ równań metodą podstawienia .

a )

{3y+2x=5

{x-y=5

b)

{y-x+4=3

{3x+2y=-7

c)

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

{(x+2)-4(y-1)=1

Answer 1

A) {3y+2x=5
     {x=5+y

   {3y+2(5+y)=5
   {x=5+y                                      3y+10+2y=5
                                                    5y= (-5)
                                                    y=(-1)
                                                    x=5+(-1)
                                                   {x=4
                                                   {y=(-1)

b) {y-x=-1
    {3x+2y=(-7)
  
     {y=x-1
     {3x+2(x-1)= (-7)                         3x+2x-2= (-7)
                                                       5x=(-5)
                                                       x = (-1)
                                                       y= (-1) -1
                                                       y= (-2)
                                                       {x= (-1)
                                                       {y= (-2)

c)
{ 3x+6+2y-4=1
{ x+2-4y+4=1

{3x+2y=(-1)
{x-4y= (-5)

{x=(-5) + 4y
{3( -5+4y) +2y= (-1)                        -15+12y+2y=(-1)
                                                       14y=14
                                                         y=1
                                                        x=(-5) + 4*1
                                                       { x=(-1)
                                                       {y=1

Pozdrawiam :)