Answer:
a₃₀ = - 18
Step-by-step explanation:
The n th term of an arithmetic sequence is
[tex]a_{n}[/tex] = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = 11 and d = a₂ - a₁ = 10 - 11 = - 1, then
[tex]a_{n}[/tex] = 11 - (n - 1) = 11 - n + 1 = 12 - n , thus
a₃₀ = 12 - 30 = - 18
