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Solve the system of linear equations and check any solutions algebraically. $$\left\\{\begin{array}{r} x+y+z+w=6 \\ 2 x+3 y\quad\quad-w=0 \\ -3 x+4 y+z+2 w=4 \\ x+2 y-z+w=0 \end{array}\right.$$

Short Answer

Expert verified
The solution to the system of equations is \(x=4\), \(y=4\), \(z=0\), and \(w=-2\).

Step by step solution

01

Setting up the equations

Write down the system of linear equations as given, in the form: \[ \begin{array}{r} x+y+z+w=6 \ 2x+3y-w=0 \ -3x+4y+z+2w=4 \ x+2y-z+w=0 \end{array} \] which can be simplified to: \[ \begin{array}{ccccccc} x &+ y &+ z &+ w &= & 6 \ 2x &+ 3y && - w &= & 0 \ -3x &+ 4y &+ z &+2w &= & 4 \ x &+ 2y & - z &+ w &= & 0 \end{array} \]
02

Simplify the Equations

Use the first equation \(x + y + z + w = 6\) to solve for x: \[x = 6 - y - z - w\]. Next, substitute \(x\) in the rest of the equations. The system of equations now simplifies to: \[ \begin{array}{ccccccc} 6 - y - z - w &+ y && - w &= & 0 \ 6 - 3y - 3z - 3w &+ 4y &+ z &+2w &= & 4 \ 6 - y - z &+ 2y & - z &+ w &= & 0 \end{array} \] which can be further simplified to: \[ \begin{array}{cccc} 6 &= & 2y &+ z \ 4 &= & y &+ 0 \ 6 &= & y &+ 0 \end{array} \]
03

Solve the Simplified Equations

From the simplified equations, it's clear that \(y=4\), \(z=0\) and \(w=-2\). Now substitute \(y=4\), \(z=0\) and \(w=-2\) in the first equation to solve for \(x\): \[x = 6 - y - z - w = 6 - 4 - 0 - (-2) = 4\]
04

Check the Solution

Finally, verify the found solutions by substituting the values of \(x\), \(y\), \(z\), and \(w\) in the original equations. It can be observed that all the original equations hold true; therefore, the solutions \(x=4\), \(y=4\), \(z=0\), and \(w=-2\) are correct.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Algebraic Solution
When tackling a system of linear equations, an algebraic solution involves finding the values of variables that satisfy all equations simultaneously. In this particular problem, our goal is to solve the system that consists of four linear equations with four unknowns: \(x\), \(y\), \(z\), and \(w\).
This algebraic approach allows us to rearrange and simplify the equations systematically to isolate each variable. By doing this, we can find a unique solution where all the equations are true at the same time. Often, variables are expressed in terms of one another to simplify the process.

For example, starting with the equation \(x + y + z + w = 6\), we can express \(x\) in terms of the other variables: \(x = 6 - y - z - w\). This expressing of one variable in terms of others and substituting back simplifies the solving process further. Through careful algebraic manipulation, it's possible to reduce the system to simpler equations, which are easier to solve.
Substitution Method
The substitution method is a common approach to solving systems of equations and is particularly effective for linear systems when one equation can easily be solved for a specific variable.
In our system, begin by isolating one variable, such as using the first equation to solve for \(x: x = 6 - y - z - w\).
Having an expression for \(x\), the next step is to substitute this into the other equations. This process reduces the number of equations and variables, often transforming a complex problem into simpler, manageable parts.

By substituting \(x\) into the remaining equations, the system of four equations is effectively reduced to three equations with three variables. Continuing with substitution, like we did in our example, helps identify specific values for variables like \(y=4\), \(z=0\), and \(w=-2\) by reducing the equations to simpler forms such as \(6 = 2y + z\).
  • Substitution streamlines solving by reducing complexity.
  • It's crucial to carefully substitute back, ensuring correctness.
  • With patience, this approach can solve most linear systems effectively.
Solution Verification
Solution verification is a vital step in solving equations to ensure the obtained solutions are correct. Once the values for \(x\), \(y\), \(z\), and \(w\) have been found, we must check them against the original equations.
This step is essential because errors can happen during algebraic manipulations, such as incorrect substitutions or arithmetic mistakes. Verification acts as a safeguard to confirm that our calculated values indeed satisfy all the original equations.

In our case, after finding that \(x=4\), \(y=4\), \(z=0\), and \(w=-2\), we substitute these values back into the original set of equations:
  • For \(x + y + z + w = 6\), substituting gives \(4 + 4 + 0 - 2 = 6\), which holds true.
  • For \(2x + 3y - w = 0\), substituting yields \(2(4) + 3(4) - (-2) = 0\), also true.
  • Continue similarly for each original equation.

If any original equation does not hold true, re-evaluate your calculations. This assurance ensures the solution is valid for the entire system.

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Most popular questions from this chapter

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