1. **State the problem:** Solve the system of equations:
$$\begin{cases} w+x+y+z=2 \\ 2w - x - y + 2z = 7 \\ 2w + 3x + 2y - z = -2 \\ 3w - 2x - y - 3z = -2 \end{cases}$$
2. **Write the system in matrix form:**
$$\begin{bmatrix} 1 & 1 & 1 & 1 \\ 2 & -1 & -1 & 2 \\ 2 & 3 & 2 & -1 \\ 3 & -2 & -1 & -3 \end{bmatrix} \begin{bmatrix} w \\ x \\ y \\ z \end{bmatrix} = \begin{bmatrix} 2 \\ 7 \\ -2 \\ -2 \end{bmatrix}$$
3. **Use elimination or substitution to solve:**
- From equation 1: $$w = 2 - x - y - z$$
- Substitute into equations 2, 3, and 4:
Equation 2:
$$2(2 - x - y - z) - x - y + 2z = 7$$
$$4 - 2x - 2y - 2z - x - y + 2z = 7$$
$$4 - 3x - 3y = 7$$
$$-3x - 3y = 3$$
$$x + y = -1$$
Equation 3:
$$2(2 - x - y - z) + 3x + 2y - z = -2$$
$$4 - 2x - 2y - 2z + 3x + 2y - z = -2$$
$$4 + x - 3z = -2$$
$$x - 3z = -6$$
Equation 4:
$$3(2 - x - y - z) - 2x - y - 3z = -2$$
$$6 - 3x - 3y - 3z - 2x - y - 3z = -2$$
$$6 - 5x - 4y - 6z = -2$$
$$-5x - 4y - 6z = -8$$
4. **Use $x + y = -1$ to express $y = -1 - x$ and substitute into the other equations:**
Equation $x - 3z = -6$ remains the same.
Equation 4:
$$-5x - 4(-1 - x) - 6z = -8$$
$$-5x + 4 + 4x - 6z = -8$$
$$-x + 4 - 6z = -8$$
$$-x - 6z = -12$$
$$x + 6z = 12$$
5. **Now solve the system:**
$$\begin{cases} x - 3z = -6 \\ x + 6z = 12 \end{cases}$$
Subtract the first from the second:
$$(x + 6z) - (x - 3z) = 12 - (-6)$$
$$x + 6z - x + 3z = 18$$
$$9z = 18$$
$$z = 2$$
6. **Find $x$ using $x - 3z = -6$:**
$$x - 3(2) = -6$$
$$x - 6 = -6$$
$$x = 0$$
7. **Find $y$ using $y = -1 - x$:**
$$y = -1 - 0 = -1$$
8. **Find $w$ using $w = 2 - x - y - z$:**
$$w = 2 - 0 - (-1) - 2 = 2 + 1 - 2 = 1$$
**Final solution:**
$$\boxed{w=1, x=0, y=-1, z=2}$$
Solve Linear System 2767B6
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