Answer:
S₁₂ = 531440
Step-by-step explanation:
There is a common ratio between consecutive terms, that is
r = 6 ÷ 2 = 18 ÷ 6 = 3
This indicates the sequence is geometric with sum to n terms
[tex]S_{n}[/tex] = [tex]\frac{a(r^n-1)}{r-1}[/tex] ( r ≠ 1 )
where a is the first term and r the common ratio
Here a = 2 and r = 3 , then
S₁₂ = [tex]\frac{2(3^{12}-1) }{3-1}[/tex]
= [tex]\frac{2(531441-1)}{2}[/tex]
= 531441 - 1
= 531440