y=ax+b and y=cx+d, these lines are parallels if a = c
2) a) y = 3x+9, the two lines are y = 3x-4 and y = 3x+5
b) y = -5x+6, the two lines are y = -5x+4 and y = -5x-2
c) y = -7x+8, the two lines are y = -7x-9 and y = -7x+7
same method with the d e and f
3) y=ax+b and y=cx+d, these lines are perpendicular if a x c=-1
a) y=3x+7, the two lines are y= (-1/3 )x +2, and y= (-1/3)x-6
b) y= -5/6x-2, the two lines are y= (6/5)x -2, and y= (6/5)x+13
c) y= - 5x+8, the two lines are y= (1/5)x - 32, and y= (1/5 )x+11
the same method for d e and f
4) coordinates of the midpoints
a) (0, 0) and (5, 15)
the midpoints is ((0+5) / 2, (0+15)/2)= (5/2, 15/2)
b) (2, 4) and (6, -5)
the midpoints is ((2+6) / 2, (4-5)/2)= (4, -1/2)
c) (3,5) and (7,5)
the midpoints is ((3+7) / 2, (5+5)/2)= (5, 5)
the same method for d e and f