Which pair of lines represent graphs that are perpendicular? a) y=-3x+7, y=-3x+2
b) y=5x+5, y=10x+5
c) 2y=4x-16, y=2x-8
d) y=9, x=5
e) y=x, y=3

Axel follows these steps to divide 40 by 9: start with 40. 1. divide by 9 and write down the remainder. 2. write a zero after the remainder. 3. repeat steps 1 and 2 until you have a remainder of zero. examine his work, and then complete the statements below.