In a science experiment, the temperature of a substance is changed from 42 degrees to -54 degrees at an average rate of -12 degrees per hour. Over how many hours does the change take place?

There are a couple of ways to do this. The easiest is to take the number of degrees between 42 and - 54 and divide by 12.

Method

the number of degrees is abs(42) + abs(-54) = 42 + 54 = 96

Now divide by 12

Hours = 96 / 12 = 8 hours.

exa:

)

3+11

14

step-by-step explanation:

from this example, we can see that subtracting with integers is the same as adding the opposite. we can solve using a number line or by using the saying "keep, change, change" to us solve. it is important to remember that we can subtract a negative and end up with a larger number than we started with.