Notice that the sequence involves subtracting 10 units from the previous term. Then, we are in the case of an arithmetic sequence with common difference = -10, since we build the next rem by subtracting 10 from the previous. so we have:
term 1 = 42
term 2 = 42 - 10 = 32
term 3 = 32 - 10 = 22
term 4 = 22 - 10 = 12
term 5 = 12 - 10 = 2
term 6 = 2 - 10 = -8
term 7 = -8 - 10 = -18