Question

x+2y=7
2x+4y=5

are the graphs of these equations perpendicular?

Answer 1

2y = -x+7 ---> y = -(1/2) x + 3.5
slope m = -1/2

4y=-2x +5 ---> y = -(1/2) x + 1.25
slope m' = -1/2

the slopes are the same. Therefore they are parallel, not perpendicular.

If they had been perpendicular, you would have found m'=-1/m