A scientist puts a substance in a freezer, where the temperature of the substance changes by º C per minute. At 8:00 PM, the temperature of– 1 9 the substance was –9ºC. Find the temperature of this substance at each time below and write a multiplication expression to represent the change in temperature.
To find the temperature of the substance at each time, we need to know the rate at which the temperature is changing (º C per minute) and the initial temperature at 8:00 PM.
Let's assume the rate of change is r º C per minute. If the substance was at -9ºC at 8:00 PM, after one minute, the temperature would change by r º C. So, at 8:01 PM, the temperature would be -9 + r º C.
Similarly, after two minutes, the temperature would change by 2r º C. So, at 8:02 PM, the temperature would be -9 + 2r º C.
Following this pattern, we can see that after t minutes, the temperature would be -9 + tr º C.
To write a multiplication expression to represent the change in temperature, we need to find the difference between the final temperature at a certain time and the initial temperature at 8:00 PM. The change in temperature can be represented as:
Change in temperature = (-9 + tr) - (-9) = tr.
So, the multiplication expression to represent the change in temperature is tr.