Równanie prostej

• 2x-y+4=0
  -y=-2x-4
  y=2x+4
  

• 7x-3=5x+2-y /-7x+3+y
  y=-7x+5x+2+3
  y=-2x+5
  

• 3(2x+5)-4(7-x)+3y=8(x-2)+2y
  6x+15-28+4x+3y=8x-16+2y
  6x+4x-8x+3y-2y=28-15-16
  2x+y=28-31
  2x+y=-3
  y=-2x-3

2(3+x)+3(-2x+4)+6y=4(3-2x)+3y
6-2x-6x+12+6y=12-8x+3y
8x-2x-6x+6y-3y=12-6-12
3y=-6 /:3
y=-6/3

y=-2

• 5(4-2x)-2(x-3)-y=2(13-6x)-y

20-10x-2x+6-y=26-12x-y

12x-10x-2x-y+y=26-20-6

0x+0y=0

0=0

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