The first four terms in the sequence an=15+6n are 21, 27, 33, and 39.
The correct option is C. 21, 27, 33, 39
From the question, the equation to calculate the nth term is given which is
an=15+6n.
Now, let a1, a2, a3 and a4 denote the first, second, third and fourth terms respectively.
For the first term, a1
n = 1,
From the given equation, an=15+6n
∴ a1 = 15 + 6(1)
a1 = 15 + 6
a1 = 21
∴The first term is 21
For the second term, a2
n = 2,
From the given equation, an=15+6n
∴ a2 = 15 + 6(2)
a2 = 15 + 12
a2 = 27
∴The second term is 27
For the third term, a3
n = 3,
From the given equation, an=15+6n
∴ a3 = 15 + 6(3)
a3 = 15 + 18
a3 = 33
∴The third term is 33
For the fourth term, a4
n = 4,
From the given equation, an=15+6n
∴ a4 = 15 + 6(4)
a4 = 15 + 24
a4 = 39
∴The fourth term is 39
Hence, the first four terms in the sequence an=15+6n are 21, 27, 33, and 39.
The correct option is C. 21, 27, 33, 39
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