A) 2x-y+1=0
x-2y+1=0;
б) 3x+2y+17=0
2x-3y+8=0;
в) 5x-y+4=0
x+5y-1=0;
г очень

a) 2x-y+1=0

x-2y+1=0

y=2x-1

x-2(2x-1)+1=0

y=2x-1

x=-1/3

y=2(-1/3)-1

x=-1/3

y=1/3

x=-1/3

(-1/3,1/3)

b)3x+2y+17=0

2x-3y+8=0

x=-2/3y-17/3

2(-2/3y)-3y+8=0

x=-2/3y-17/3

y=-10/13

x=-2/3(-10/13)-17/3

y=-10/13

x=-67/13

y=-10/13

(-67/13,-10/13)

в) 5x-y+4=0

x+5y-1=0

y=5x+4

x+5(5x+4)-1=0

y=5x+4

x=-19/26

y=5(-19/26)+4

x=-19/26

y=9/26

x=-19/26

(-19/26,9/26)

г) 5x-3y+1=0

15x+9y-7=0

x=3/5y-1/5

15(3/5y-1/5)+9y-7=0

x=3/5y-1/5

y=5/9

x=3/5*5,9-1/5

y=5/9

x=2/15

y=5/9

(2/15,5/9)