are the following lines parallel, perpendicular or neither 4x+5y=7 5x+4y=10
m1 = -A/B = -4/5.
m2 = -A/B = -5/4.
They are not parallel, because the slopes are not =.
They are not perpendicular, because the slopes are not neg. reciprocals.
m2 would have to be +5/4.