Answer:
Step-by-step explanation:
Given
Garden: 
One Bag: 
Requires
Determine the number of bags to cover the whole garden
This is calculated as thus;

Expand the numerator



Express 81 as 9²

Evaluate as difference of two squares


Hence, the number of bags is 
Answer:
c
Step-by-step explanation:
Please let me know if you want me to add an explanation as to why this is the answer. I can definitely do that, I just wouldn’t want to write it if you don’t want me to :)
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