Question 811800
parallel-- have the same slope
perpendicular --the slopes multiplied together =-1
neither they cross and aren't perpendicular 

a. y=2x+5
2x+y=9 
y=-2x+9
not perpendicular nor parallel
meet at
x = 1,   y = 7
b. 3x+4y=7
4y=-3x+7
y=-3/4x+7/4

4x=3y-8 
3y=4x+8
y=4/3x+8/3
they are perpendicular
-3/4*4/3=-1
x = -11/25,   y = 52/25