Answer :

To solve the given problem, we'll need to evaluate the sum of the series [tex]\( \sum_{n=1}^3 (4n^2 + 3) \)[/tex].

1. Find the individual terms of the series:
- When [tex]\( n = 1 \)[/tex]:
[tex]\[ 4(1)^2 + 3 = 4 \cdot 1 + 3 = 4 + 3 = 7 \][/tex]
- When [tex]\( n = 2 \)[/tex]:
[tex]\[ 4(2)^2 + 3 = 4 \cdot 4 + 3 = 16 + 3 = 19 \][/tex]
- When [tex]\( n = 3 \)[/tex]:
[tex]\[ 4(3)^2 + 3 = 4 \cdot 9 + 3 = 36 + 3 = 39 \][/tex]

2. List the terms of the series:
[tex]\[ 7, 19, 39 \][/tex]

3. Sum the terms:
[tex]\[ 7 + 19 + 39 = 65 \][/tex]

Therefore, the sum of the series [tex]\( \sum_{n=1}^3 (4n^2 + 3) \)[/tex] is [tex]\( 65 \)[/tex].

Enter your answer in the box:
[tex]\[ \boxed{65} \][/tex]