D is integer and rest r rational I guess
If the arrow is pointing downwards, it means it is negative (like the one in your picture). If the arrow points upwards, it is positive!! :)
It would be A, but it ultimately matters what formula you are using.
Answer:
500cm2
Step-by-step explanation:
2(9×20)+(7×20)
=360+140=500cm2
Answers:
5) product is 
6) product is 
7) product is 
8) product is 
9) product is 
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Explanation:
For each of these questions, you'll multiply the term outside by each term inside the parenthesis. I'm using the distributive property.
In problem 5, we multiply the outer 7a by the following terms inside like so

The other problems will have similar steps.
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A useful rule to keep in mind is that 
For example, 