Answer:
1) first two (A & B)
2. -1,533
Step-by-step explanation:
Sum to infinity is finite when
-1 < r < 1
Option 1: r = -¼
Option 2: r = 27/81 = ⅓
Option 3: r = 3/2
Option 4: r = 17.75/7.1 = 2.5
a = -3
r = -6/-3 = 2
S9 = -3 × (2⁹ - 1)/(2 - 1)
= -1533
