Answer :

Let's find the first 4 terms for each sequence provided:

### Part a) [tex]\(a_n = n + 4\)[/tex]

To find the first 4 terms, we will substitute [tex]\( n = 1, 2, 3, 4 \)[/tex] into the given formula [tex]\(a_n = n + 4\)[/tex].

1. For [tex]\( n = 1 \)[/tex]:
[tex]\[ a_1 = 1 + 4 = 5 \][/tex]

2. For [tex]\( n = 2 \)[/tex]:
[tex]\[ a_2 = 2 + 4 = 6 \][/tex]

3. For [tex]\( n = 3 \)[/tex]:
[tex]\[ a_3 = 3 + 4 = 7 \][/tex]

4. For [tex]\( n = 4 \)[/tex]:
[tex]\[ a_4 = 4 + 4 = 8 \][/tex]

Thus, the first 4 terms of the sequence [tex]\(a_n = n + 4\)[/tex] are:
[tex]\[ [5, 6, 7, 8] \][/tex]

### Part b) [tex]\(a_n = 12 - 3n\)[/tex]

To find the first 4 terms, we will substitute [tex]\( n = 1, 2, 3, 4 \)[/tex] into the given formula [tex]\(a_n = 12 - 3n\)[/tex].

1. For [tex]\( n = 1 \)[/tex]:
[tex]\[ a_1 = 12 - 3 \cdot 1 = 12 - 3 = 9 \][/tex]

2. For [tex]\( n = 2 \)[/tex]:
[tex]\[ a_2 = 12 - 3 \cdot 2 = 12 - 6 = 6 \][/tex]

3. For [tex]\( n = 3 \)[/tex]:
[tex]\[ a_3 = 12 - 3 \cdot 3 = 12 - 9 = 3 \][/tex]

4. For [tex]\( n = 4 \)[/tex]:
[tex]\[ a_4 = 12 - 3 \cdot 4 = 12 - 12 = 0 \][/tex]

Thus, the first 4 terms of the sequence [tex]\(a_n = 12 - 3n\)[/tex] are:
[tex]\[ [9, 6, 3, 0] \][/tex]

In summary, for the given sequences:

a) The first 4 terms of [tex]\(a_n = n + 4\)[/tex] are [tex]\([5, 6, 7, 8]\)[/tex].

b) The first 4 terms of [tex]\(a_n = 12 - 3n\)[/tex] are [tex]\([9, 6, 3, 0]\)[/tex].