Answer:
-53, f(n) = -6(n-1) + 13
Step-by-step explanation:
given the equation to this linear/arithmetic sequence for the nth term: f(n) = -6(n-1) + 13
f(12) = -6(12-1) + 13
f(12) = -6(11) + 13
f(12) = -66 + 13
f(12) = -53
*substitute and simplify*
______________
f(n) = f(1) + d(n-1)
given f(1) = 13, f(2) = 7, and f(3) = 1
7-13 = 1-7 = -6 = d
= f(1) + d(n-1)
f(1) = 13 so
the equation must be f(n) = 13 - 6(n-1) or -6(n-1) + 13
