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.

Answer 1

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.