Let a(0) represent the first term; its value is -10. The next term is found by subtracting 2 from -10, obtaining -12. Each new term is created by subtracting 2 from the previous one. Thus, the formula for the nth term is
a(n) = a(0)-2(n-1), or a(n) = -10-2(n-1).
First term: -10
Second: -12
Third: -14,
....
Tenth term: a(10) = -10-2(10-1) = -10 - 18 = -28
