Answer:
100
Step-by-step explanation:
200 + 6d = 800
Subtract 200 from each side: 6d=600
Divide 6 from each side: d=100
d =100
200 + 6d=800
Subtract 200 from each side
200-200 + 6d=800-200
6d = 600
Divide each side by 6
6d/6 = 600/6
d = 100
