1. **State the problem:** We have the homogeneous system of equations:
$$x + 3y = 0$$
$$2x + 6y = 0$$
We want to prove using the augmented matrix that the system has nontrivial solutions and find two different solutions.
2. **Write the augmented matrix:**
$$\left[\begin{array}{cc|c} 1 & 3 & 0 \\ 2 & 6 & 0 \end{array}\right]$$
3. **Perform row operations to reduce the matrix:**
Replace row 2 by row 2 minus 2 times row 1:
$$\left[\begin{array}{cc|c} 1 & 3 & 0 \\ 2 & 6 & 0 \end{array}\right] \xrightarrow{R_2 \to R_2 - 2R_1} \left[\begin{array}{cc|c} 1 & 3 & 0 \\ \cancel{2} & \cancel{6} & 0 \end{array}\right] = \left[\begin{array}{cc|c} 1 & 3 & 0 \\ 0 & 0 & 0 \end{array}\right]$$
4. **Interpret the reduced matrix:**
The second row is all zeros, indicating the system has infinitely many solutions.
5. **Express variables:**
From the first row:
$$x + 3y = 0 \implies x = -3y$$
6. **Find two different solutions:**
Choose arbitrary values for $y$:
- For $y=1$, $x = -3(1) = -3$, so solution is $(-3,1)$.
- For $y=2$, $x = -3(2) = -6$, so solution is $(-6,2)$.
7. **Conclusion:**
The system has nontrivial solutions because the determinant of the coefficient matrix is zero and the system is dependent.
**Final answer:** Two different solutions are $(-3,1)$ and $(-6,2)$.
Homogeneous System C0Df6B
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