Which set of lines is perpendicular?
the line between the points (1,3) and (3,5), and y = 4_x_ + 7
y = 3_x_ + 5 and y = 5_x_ + 3
y = 3_x_/5 – 3 and y = 5_x_/3 + 3
y = x – 1/2 and y = –x + 1/2
the line between the points (7,4) and (4,7), and the line between the points (3,9) and (4,8)
