Find the value of `16a^(2) + 24a + 9` when a = 9.

Answer

To find the value of the expression \(16a^2 + 24a + 9\) when \(a = 9\), we will follow these steps:

### Step 1: Substitute the value of \(a\)
We start by substituting \(a\) with \(9\) in the expression:
\[ 16(9)^2 + 24(9) + 9 \]

### Step 2: Calculate \(9^2\)
Next, we calculate \(9^2\):
\[ 9^2 = 81 \]
So, the expression now becomes:
\[ 16(81) + 24(9) + 9 \]

### Step 3: Multiply \(16\) by \(81\)
Now we calculate \(16 \times 81\):
\[ 16 \times 81 = 1296 \]
The expression now looks like:
\[ 1296 + 24(9) + 9 \]

### Step 4: Calculate \(24 \times 9\)
Next, we calculate \(24 \times 9\):
\[ 24 \times 9 = 216 \]
Now the expression is:
\[ 1296 + 216 + 9 \]

### Step 5: Add the values together
Finally, we add all the values together:
\[ 1296 + 216 + 9 = 1521 \]

### Final Answer
Thus, the value of the expression \(16a^2 + 24a + 9\) when \(a = 9\) is:
\[ \boxed{1521} \]