X+2y=5 2y=-x+5 y=-1/2x+5/2 k=-1/2

2x+4y=8 x+2y=4 y=-1/2x+2 k=-1/2

(-1/2)*(-1/2)=1/4

so the two equations are not perpendicular.

2x+4y=8 x+2y=4 y=-1/2x+2 k=-1/2

(-1/2)*(-1/2)=1/4

so the two equations are not perpendicular.