Answer:
The nth term of the arithmetic sequence is;
90 - 3n
Step-by-step explanation:
Here, we want to find an expression for the nth term of the sequence
Mathematically, let us determine the type of sequence
As we can see;
84 - 87 = 81-84 = -3
The difference between the terms is a constant; this means that the sequence is arithmetic
The nth term of an arithmetic sequence can be represented by;
Tn = a + (n-1)d
in this case, a is the first term of the sequence = 87
d is the common difference of the sequence = -3
The nth term is thus;
Tn = 87 + (n-1)-3
Tn = 87 - 3n + 3
Tn = 87 + 3 - 3n
Tn = 90 - 3n
