Which expression has the same sum as the one below?

–15 + 6

a 15 + 6
b –6 + (–15)
c 15 + (–6)
d 6 + (–15)

The boiling point of water at an elevation of 0 feet is 212 degrees fahrenheit (°f). for every 1,000 feet of increase in elevation, the boiling point of water decreases by about 2°f. which of the following represents this relationship if b is the boiling point of water at an elevation of e thousand feet? a) e = 2b - 212 b) b = 2e - 212 c) e = -2b + 212 d) b = -2e + 212

If t17 = 3 (t5) in an arithmetic progression, find t1 in terms of d.

The anwser cause i do not understand just plez