Chapter 3: Problem 6
Solve each system of equations. \(x+y+z=12\) \(6 x-2 y-z=16\) \(3 x+4 y+2 z=28\)
Short Answer
Expert verified
The solution is \(x = 2\), \(y = 2\), \(z = 8\).
Step by step solution
01
Write the System of Equations
First, we need to clearly list the system of equations we are solving: 1) \(x + y + z = 12\) 2) \(6x - 2y - z = 16\) 3) \(3x + 4y + 2z = 28\).
02
Eliminate One Variable
We will eliminate variable \(z\) by manipulating the equations. Let's eliminate \(z\) from equations (1) and (2).First, multiply equation (1) by 1 to keep it the same, then add to equation (2):\[(x + y + z) + (6x - 2y - z) = 12 + 16\]\[7x - y = 28 \ ext{(Equation 4)}\]
03
Eliminate the Same Variable Again
Next, eliminate \(z\) using equations (1) and (3). First, multiply equation (1) by 2 to match the coefficients of \(z\):\[ 2(x + y + z) = 2(12) \] \[ 2x + 2y + 2z = 24 \] Subtract this from equation (3):\[(3x + 4y + 2z) - (2x + 2y + 2z) = 28 - 24 \]\[x + 2y = 4 \ ext{(Equation 5)}\]
04
Solve the New System
Now solve the new system of equations formed by equations (4) and (5):1) \(7x - y = 28\) 2) \(x + 2y = 4\).Substitute \(y = 2\) from substituting \(x\) from equation (5) into equation (4):Using equation (5): \(y = 4 - x\).
05
Substitute Back
Substitute \(x = 2\) into \(x + 2y = 4\):\[2 + 2y = 4\]\[\,\, 2y = 4 - 2\]\[y = 2\]Now substitute back to find \(z\) using equation (1):\[ 2 + 2 + z = 12 \]\[ z = 12 - 4 \]\[ z = 8 \]
06
Verify the Solution
Verify the solution by substituting \(x = 2\), \(y = 2\), and \(z = 8\) back into the original system:1) \(2 + 2 + 8 = 12\)2) \(6(2) - 2(2) - 8 = 16\)3) \(3(2) + 4(2) + 2(8) = 28\)All checks are true, confirming the solution.
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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 equations, we often use algebraic methods to find the values of unknowns. Here, the goal is to solve for the variables \(x\), \(y\), and \(z\) in a set of three equations:
- \(x + y + z = 12\)
- \(6x - 2y - z = 16\)
- \(3x + 4y + 2z = 28\)
Variable Elimination
Variable elimination is a key step in solving systems of equations. This is where you aim to simplify the equations by removing one variable at a time, making the system easier to solve. Let's focus on eliminating \(z\) first. We take two equations and manipulate them to cancel out \(z\), leading to a simpler system. This involves:
- Adjusting coefficients of \(z\) in the equations.
- Adding/subtracting equations.
- Seeing how these changes create a new equation where one variable is removed.
Mathematical Reasoning
Mathematical reasoning forms the backbone of solving equations through a structured method. It applies logic and careful calculation to arrive at a solution, always ensuring accuracy. In the example, we reason through steps such as:
- Checking solutions by substituting back into original equations to confirm they hold true.
- Recognizing patterns or relationships that simplify the problem.