Answer:
7.211
Step-by-step explanation:
-For two points in the complex plane, the distance between the points is the modulus of the of the difference of the two complex numbers.
-Point 2-4i has the coordinates (2,-4)
-Point 6+i has the coordinates (6,1)
#We must find the distance between the two coordinates (2,-4) and (6,1):

Hence, the distance between the two points is 7.211
The expression that shows the total gallons is 0.5gallon/1 day*16cups/1gallon * 7days/1week
<h3>Dimensional Analysis</h3>
From the given question, we are told that Katrina drinks 0.5 gallons per day. In order to determine the total cup that she drank in a a week, we will have:
Total gallons in a week. = 0.5gallons/1 day * 7days/1
Total gallons in a week = 3.5 gallons
Since 1 gallon. = 16 cups, then;
3.5 gallons = 16cups/1gallon * 3.5gallons
3.5 gallons = 56 cups
Hence the expression that shows the total gallons is 0.5gallon/1 day*16cups/1gallon * 7days/1week
Learn more on dimensional analysis here: brainly.com/question/18559676
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I needed help with that too