Answer: 4 .
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n/2 = 5 - 3 ;
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n/2 = 2 ;
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n = 2*2 ;
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n = 4 .
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The answer is 30 60 and 90 because those are the only 3 numbers that are divisible by both 3 and 10 and are two digits.
It is 23.917 because 51.92-28.003= to that number
The third option. you can always substitute the points into your equation to see if the equation is true or not.