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Solve the system of linear equations, if possible. State any solutions and classify each system as consistent independent, consistent dependent, or inconsistent. If not possible, enter \( D N E \) in part (b). If the system is dependent, enter \( x \) and \( y \) in terms of \( z \). \( x+y+z=-4 \) \( -3 x-y+z=0 \) \( 5 x+4 y+3 z=-14 \) (a) The system of equations is: Consistent dependent. Inconsistent. Consistent independent. (b) The solution to the system is \( x= \) or \( x= \)

Ask by Dawson May. in the United States
Mar 21,2025

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Answer

The system is consistent and dependent. The solutions are: \[ x = z + 2,\quad y = -2z - 6,\quad z = z \] where \( z \) is any real number.

Solution

**Step 1. Express one variable in terms of the others.** From the first equation, \[ x+y+z=-4, \] solve for \( z \): \[ z=-4-x-y. \] **Step 2. Substitute into the second equation.** The second equation is \[ -3x-y+z=0. \] Substitute \( z=-4-x-y \): \[ -3x-y+(-4-x-y)=0. \] Simplify: \[ -3x-y-4-x-y=0, \] \[ -4x-2y-4=0. \] Add 4 to both sides: \[ -4x-2y=4. \] Multiply by \(-1\): \[ 4x+2y=-4. \] Divide by 2: \[ 2x+y=-2. \] Solve for \( y \): \[ y=-2-2x. \] **Step 3. Express \( z \) using the value of \( y \).** Recall \[ z=-4-x-y. \] Substitute \( y=-2-2x \): \[ z=-4-x-(-2-2x)= -4-x+2+2x. \] Combine like terms: \[ z=(-4+2)+( -x+2x)= -2+x. \] Thus, \[ z=x-2. \] **Step 4. Substitute \( y \) and \( z \) into the third equation to verify consistency.** The third equation is \[ 5x+4y+3z=-14. \] Substitute \( y=-2-2x \) and \( z=x-2 \): \[ 5x+4(-2-2x)+3(x-2)=-14. \] Simplify: \[ 5x-8-8x+3x-6=-14. \] Combine like terms: \[ (5x-8x+3x) + (-8-6) = 0x -14=-14. \] This simplifies to: \[ -14=-14, \] which is always true. Hence, the third equation does not add any new information. **Step 5. Classify the system.** Since the third equation does not provide new information and the other two equations are consistent, the system has infinitely many solutions. It is a **consistent dependent** system. **Step 6. Express the solution in terms of \( z \).** We have: \[ z=x-2 \quad \Longrightarrow \quad x=z+2. \] And from earlier: \[ y=-2-2x. \] Substitute \( x=z+2 \): \[ y=-2-2(z+2)=-2-2z-4=-2z-6. \] **Final Answers:** (a) The system of equations is: **Consistent dependent.** (b) The solution to the system is \[ x=z+2,\quad y=-2z-6,\quad z=z\quad (\text{where } z \in \mathbb{R}). \]

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To solve the given system of equations, we can represent it as an augmented matrix and proceed with a row reduction method. The equations are: 1. \( x + y + z = -4 \) 2. \( -3x - y + z = 0 \) 3. \( 5x + 4y + 3z = -14 \) Arranging it into an augmented matrix, we have: \[ \begin{bmatrix} 1 & 1 & 1 & | & -4 \\ -3 & -1 & 1 & | & 0 \\ 5 & 4 & 3 & | & -14 \end{bmatrix} \] Now, we would apply row operations to reduce it: 1. Replace Row 2 by Row 2 + 3 * Row 1. 2. Replace Row 3 by Row 3 - 5 * Row 1. After performing those operations, we get: \[ \begin{bmatrix} 1 & 1 & 1 & | & -4 \\ 0 & 2 & 4 & | & -12 \\ 0 & -1 & -2 & | & 6 \end{bmatrix} \] Next, we simplify Row 2 and Row 3 further. After continuing the row operations and reaching a final reduced form, we eventually notice that the system yields a dependent scenario, leading us to express the variables in terms of one another. Ultimately, the conclusion shows: (a) The system of equations is: Consistent dependent. (b) To find the solution, we can express \( x \) and \( y \) in terms of \( z \): Let \( z = t \) (free variable), Then, from the first equation: - \( x + y + t = -4 \) From the second: - \( -3x - y + t = 0 \) Rearranging these gives two equations that can be solved in terms of \( t \). So you might arrive at: - \( x = -4 - t - y \) - \( y = t + 6 \), and then substitute to find \( x \). After calculations, you could say: \( x = -10 + k, y = k - 2, z = k \) (where \( k \) represents \( t \) which is free). This means: The solution to the system is \((x, y, z) = (-10 + k, k - 2, k) \) for any real number \( k \). Have fun exploring how these dimensions of algebra weave together! Remember, linear systems can be full of surprises, just like a bake-off where not every cake rises!

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