Math homework is nice but also can be complicated.

Question

At the beginning of a labratory experiment the temperature of a substance is - 12.6 degree Celsius. during the experiment the temperature of the substance decreases 7.5 degrees Celsius. what is the final temperature of the substance

Answer 1

Decreases means to subtract, so if you start at -12.6 degrees and decrease the temperature by 7.5 degrees:

 

-12.6 - 7.5 = -20.1 degrees

 

Since both numbers are negatives, you add the amounts together. Think of a number line. You start at -12.6, then move left 7.5 from there. You end up at -20.1.

Answer 2

I think that you will find that this should be -12.6 subtract (because there's a DECREASE) 7.5, giving a final answer -20.1. I answered this question (which was submitted two consecutive times by student) in the above manner earlier, and answered this particular submission by commenting that it had been answered already (was duplicate submission).

Answer 3

-12.6 - 7.5 = -20.1^oC.

Answer 4

-12.6 + 7.5 = -5.1