Answer:
-64 is the 26th number
it's an arithmetic sequence because the difference between the number is constant : -3
they are all -3 in difference
Explanation:
an = a1 + (n-1)d
an = the nᵗʰ term in the sequence
a1=the first term in the sequence
d=the common difference between terms
-64 = 11 + (n - 1)-3
-64=11 -3n+3
-78 = -3n
n = 26