Answer:
-52 1/2 = a1
Step-by-step explanation:
an = a1 + d(n-1) is the equation for an arithmetic sequence
a27 = -1/2
d=2
n =27
substitute in what we know
-1/2 = a1 + 2 (27-1)
-1/2 = a1 +2 * 26
-1/2 = a1 + 52
subtract 52 from both sides
-1/2 -52 = a1
-52 1/2 = a1
