Treść zadania

Najlepsze rozwiązanie

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  sonar 6.4.2011 (08:24)

  A.
  2x + y = -4
  x - y = -2
  
  y = -4 -2x
  x-y = -2
  
  y= -4 -2x
  x -(-4 -2x) = -2
  
  y= - 4 - 2x
  x+4 + 2x = -2
  
  y= -4 - 2x
  3x = -2 -4
  
  y= -4 - 2x
  3x= -6
  
  y= -4 - 2x
  x= -6 : 3
  
  y = -4 - 2x
  x= -2
  
  y = -4 -2 (-2)
  x= -2
  
  y = -4 -(-4)
  x= -2
  
  y= -4 + 4
  x= -2
  
  y=0
  x= -2
  
  
  spr.
  2x + y = -4
  2* (-2) + 0 = -4
  -4 = -4
  L=P
  
  
  
  B.
  5x -2y = 4
  x + y = 5
  
  5x -2y = 4
  x= 5 - y
  
  5*(5-y) -2y = 4
  x= 5 -y
  
  25 - 5y - 2y = 4
  x= 5 -y
  
  -7y = 4 -25
  x= 5 -y
  
  -7y = -21
  x= 5-y
  
  y= -21 : (-7)
  x= 5-y
  
  y=3
  x= 5-3
  
  y=3
  x=2
  
  
  spr.
  5x -2y = 4
  5*2 - 2*3= 4
  10 - 6 = 4
  4=4
  L=P
  
  
  
  C.
  2x +4y = 5y -1
  y +5 = 0
  
  2x +4y- 5y = -1
  y= -5
  
  2x -y = -1
  y = - 5
  
  2x - (-5) = -1
  y = -5
  
  2x + 5 = -1
  y = -5
  
  2x= -1 -5
  y = -5
  
  2x= - 6
  y= -5
  
  x= - 6 : 2
  y = -5
  
  x= - 3
  y = -5
  
  
  spr.
  2x +4y = 5y -1
  2* (- 3) + 4 * (-5) = 5 *(-5) -1
  - 6 + ( -20) = -25 -1
  - 6 - 20 = -26
  -26=-26
  L=P
  
  
  
  D.
  y - 3 = 0
  3x - 6y = 12
  
  y= 3
  3x - 6y = 12
  
  y=3
  3x -6*3= 12
  
  y=3
  3x - 18 = 12
  
  y=3
  3x= 12 + 18
  
  y=3
  3x= 30
  
  y= 3
  x= 30 : 3
  
  y =3
  x= 10
  
  
  spr.
  3x - 6y = 12
  3* 10 - 6 * 3= 12
  30 - 18 = 12
  12= 12
  L=P

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