Someone help me please and try not to make the answer stupid

While scuba diving, rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. what expression can be used to find rajeev's new position? 12.6 – 8.7 –12.6 – 8.7 –12.6 – (–8.7) 12.6 – (–8.7)

45 was divided by a power of ten to get 4.5. what power of ten was it divided by? people 4.5

25 ! i need asap! ! ill mark brainliest!