To determine the type of conic section represented by the given equation, we need to complete the square for both the \(x\) and \(y\) terms. This will help us rewrite the equation in a standard form that can be easily identified as an ellipse, parabola, hyperbola, or degenerate conic. Once the equation is in standard form, we can identify the conic section and, if applicable, find its properties such as center, foci, vertices, and axes lengths.
The given equation is:
\[
3x^2 + 4y^2 - 18x - 8y + 31 = 0
\]
First, we rearrange the terms to group the \(x\) and \(y\) terms:
\[
3x^2 - 18x + 4y^2 - 8y = -31
\]
For the \(x\) terms, factor out the coefficient of \(x^2\):
\[
3(x^2 - 6x) + 4y^2 - 8y = -31
\]
Complete the square inside the parentheses:
- Take half of the coefficient of \(x\), which is \(-6\), giving \(-3\).
- Square it to get \(9\).
- Add and subtract \(9\) inside the parentheses:
\[
3(x^2 - 6x + 9 - 9) + 4y^2 - 8y = -31
\]
This simplifies to:
\[
3((x-3)^2 - 9) + 4y^2 - 8y = -31
\]
Distribute the \(3\):
\[
3(x-3)^2 - 27 + 4y^2 - 8y = -31
\]
For the \(y\) terms, factor out the coefficient of \(y^2\):
\[
3(x-3)^2 + 4(y^2 - 2y) = -31 + 27
\]
Simplify the right side:
\[
3(x-3)^2 + 4(y^2 - 2y) = -4
\]
Complete the square inside the parentheses for \(y\):
- Take half of the coefficient of \(y\), which is \(-2\), giving \(-1\).
- Square it to get \(1\).
- Add and subtract \(1\) inside the parentheses:
\[
3(x-3)^2 + 4((y-1)^2 - 1) = -4
\]
This simplifies to:
\[
3(x-3)^2 + 4(y-1)^2 - 4 = -4
\]
Distribute the \(4\):
\[
3(x-3)^2 + 4(y-1)^2 - 4 = -4
\]
Add \(4\) to both sides:
\[
3(x-3)^2 + 4(y-1)^2 = 0
\]
The equation \(3(x-3)^2 + 4(y-1)^2 = 0\) suggests that both squared terms must be zero for the equation to hold, which implies:
\[
(x-3)^2 = 0 \quad \text{and} \quad (y-1)^2 = 0
\]
Thus, \(x = 3\) and \(y = 1\). This is a single point, indicating a degenerate conic.
The graph of the equation is a degenerate conic. Therefore, the answer is:
\[
\boxed{\text{degenerate conic}}
\]