Odpowiedź :
x-2y-1=0
-2y=-x+1 |·(-1)
2y=x-1 |:2
y=1/2x-1/2
A=(-1;2)
2=1/2·(-1)+b
2=-1/2+b
-b=-1/2-2
-b=-5/2 |·(-1)
b=5/2
y=1/2x+5/2
x-2y-1=0
-2y=-x+1 |·(-1)
2y=x-1 |:2
y=1/2x-1/2
A=(-1;2)
2=1/2·(-1)+b
2=-1/2+b
-b=-1/2-2
-b=-5/2 |·(-1)
b=5/2
y=1/2x+5/2