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.