1. **Stating the problem:** Solve the system of linear equations for $x_3$:
$$\begin{cases} 2x_1 - x_2 - x_3 = 4 \\ 3x_1 + 4x_2 - 2x_3 = 11 \\ 3x_1 - 2x_2 + 4x_3 = 11 \end{cases}$$
2. **Method:** We will use substitution or elimination to find $x_3$. First, express $x_3$ from the first equation:
$$2x_1 - x_2 - x_3 = 4 \implies x_3 = 2x_1 - x_2 - 4$$
3. **Substitute $x_3$ into the second and third equations:**
Second equation:
$$3x_1 + 4x_2 - 2(2x_1 - x_2 - 4) = 11$$
Simplify:
$$3x_1 + 4x_2 - 4x_1 + 2x_2 + 8 = 11$$
$$(-x_1) + 6x_2 + 8 = 11$$
$$-x_1 + 6x_2 = 3$$
Third equation:
$$3x_1 - 2x_2 + 4(2x_1 - x_2 - 4) = 11$$
Simplify:
$$3x_1 - 2x_2 + 8x_1 - 4x_2 - 16 = 11$$
$$11x_1 - 6x_2 - 16 = 11$$
$$11x_1 - 6x_2 = 27$$
4. **Now solve the system:**
$$\begin{cases} -x_1 + 6x_2 = 3 \\ 11x_1 - 6x_2 = 27 \end{cases}$$
Add the two equations to eliminate $x_2$:
$$(-x_1 + 6x_2) + (11x_1 - 6x_2) = 3 + 27$$
$$10x_1 = 30 \implies x_1 = 3$$
5. **Find $x_2$ using $-x_1 + 6x_2 = 3$:**
$$-3 + 6x_2 = 3 \implies 6x_2 = 6 \implies x_2 = 1$$
6. **Find $x_3$ using $x_3 = 2x_1 - x_2 - 4$:**
$$x_3 = 2(3) - 1 - 4 = 6 - 1 - 4 = 1$$
**Final answer:**
$$\boxed{x_3 = 1}$$
Solve X3 8De685
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