Can someone help and explain it to me please, thank you :)

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)

Which representation has a constant of variation of -2.5

Which two undefined geometric terms always describe figures with no beginning or end?