To solve the math question \( I + IV + IX \) in Roman numerals, we first need to convert the Roman numerals to their integer values:
- \( I = 1 \)
- \( IV = 4 \)
- \( IX = 9 \)
Now, we add these values together:
\[ 1 + 4 + 9 = 14 \]
Now, we convert \( 14 \) back to Roman numerals, which is \( XIV \).
From the options you provided, the correct answer is:
a. 14