The temperature was 29*f. by the end of the day, the temperature dropped to -7*f. what was the total distance in the temperature change?

It dropped from 29 to -7

So going from 29 to 0, is a total of a 29 degree change.
And then going from 0 to -7 is a total of a 7 degree change.

Thus the total change in temperature is 29 + 7 = 36.

Change in temp is just the maginitude of the difference between the two temperatues

|delta T|

=|T2-T1|  OR |T1-T2|(same answer)
=|-7-21|

=28

The answer is the third choice