In this case the temperature depends on the hour. So temperature is your X and hour is your Y variable. When h=0, x=0. So the 21*C is you x=0 or y-int point.
If we are trying to match the equation for a line of y=mx+b, 21*C=b.
Our rate of change is -4*C/h, which is our m variable.
So y=(-4)x+(21)
OR in this case, t=-4h+21.
Answer D.
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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