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Ch. 5 - Systems of Equations and Inequalities
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
All textbooksBlitzer 8th EditionCh. 5 - Systems of Equations and InequalitiesProblem 7
Chapter 6, Problem 7

Solve each system in Exercises 5–18. {4x−y+2z=11x+2y−z=−12x+2y−3z=−1\(\begin{cases}\)4x - y + 2z = 11 \(\x\) + 2y - z = -1 \\2x + 2y - 3z = -1\(\end{cases}\)

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1
Write down the system of equations clearly: \[4x - 0y + 2z = 11\] \[x + 2y - z = -1\] \[2x + 2y - 3z = -1\]
Since the first equation has no y term, focus on expressing one variable in terms of the others from one of the simpler equations. For example, from the second equation, solve for \(x\) in terms of \(y\) and \(z\): \[x = -1 - 2y + z\]
Substitute the expression for \(x\) from step 2 into the first and third equations to eliminate \(x\). This will give you two equations with only \(y\) and \(z\) as variables.
Solve the resulting two-variable system from step 3 using either substitution or elimination to find values for \(y\) and \(z\).
Once you have \(y\) and \(z\), substitute these values back into the expression for \(x\) from step 2 to find the value of \(x\). This completes the solution for the system.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Systems of Linear Equations

A system of linear equations consists of two or more linear equations with the same variables. The goal is to find values for the variables that satisfy all equations simultaneously. Understanding how to interpret and set up these systems is essential for solving them.
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Methods for Solving Systems (Substitution, Elimination, and Matrix Methods)

Common techniques to solve systems include substitution, elimination, and using matrices (such as Gaussian elimination). These methods help reduce the system to simpler forms, making it easier to find the values of variables that satisfy all equations.
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Consistency and Types of Solutions

A system can have one unique solution, infinitely many solutions, or no solution. Recognizing the system's consistency helps determine the nature of the solution set, which is crucial when interpreting the results of solving the system.
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Textbook Question

In Exercises 5–18, solve each system by the substitution method. {x+3y=8y=2x−9\(\begin{cases}\)x + 3y = 8 \(\y\) = 2x - 9\(\end{cases}\)

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Textbook Question

Graph each inequality. y>2x−1

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Textbook Question

Write the form of the partial fraction decomposition of the rational expression. It is not necessary to solve for the constants. x3+x2(x2+4)2\(\frac{x^3 + x^2}{(x^2 + 4)^2}\)

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Textbook Question

In Exercises 1–18, solve each system by the substitution method.{x2+y2=25x−y=1\(\begin{cases}\)x^2 + y^2 = 25 \(\x\) - y = 1\(\end{cases}\)

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Textbook Question

In Exercises 1–8, write the form of the partial fraction decomposition of the rational expression. It is not necessary to solve for the constants. (7x2 -9x+3)/(x2+7)2

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