Given the first five terms of the sequence 19, 15, 11, 7, 3 . . . , use subscript notation to describe a7 .(1 point) Responses a7=−9 a subscript 7 baseline equals negative 9 a7=−5 a subscript 7 baseline equals negative 5 a7=−1 a subscript 7 baseline equals negative 1 a7=−4

1 answer

To find \( a_7 \) in the given sequence 19, 15, 11, 7, 3, let's first analyze the sequence.

The first term \( a_1 = 19 \). The second term \( a_2 = 15 \). The third term \( a_3 = 11 \). The fourth term \( a_4 = 7 \). The fifth term \( a_5 = 3 \).

We can see that the sequence is decreasing, and it is decreasing by 4 each time:

  • \( 19 - 4 = 15 \)
  • \( 15 - 4 = 11 \)
  • \( 11 - 4 = 7 \)
  • \( 7 - 4 = 3 \)

Now, we can express the general term of the sequence, \( a_n \):

The \( n \)-th term can be calculated using the formula:

\[ a_n = 19 - 4(n - 1) \]

Now, we will find \( a_7 \):

\[ a_7 = 19 - 4(7 - 1) = 19 - 4(6) = 19 - 24 = -5 \]

Thus, \( a_7 = -5 \).

So the correct response is:

a7 = -5.