Answer:
Kendal will be 60 meters away from the library after 80 seconds and again after 100 seconds.
Explanation:
6s -540 = 60 or 6s - 540 = -60
First equation
addition property of equality: 6s -540 + 540 = 60 + 540
simplify: 6s = 600
division property of equality: 6s/6 = 600/6
simplify: s = 100
Second equation
addition property of equality: 6s -540 + 540 = -60 + 540
simplify: 6s = 480
division property of equality: 6s/6 = 480/6
simplify: s = 80