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Solving Systems of Equations Using Matrices. $$\left\\{\begin{aligned}5 x+3 y &=-1 \\\\-10 x-6 y &=2\end{aligned}\right.$$

Short Answer

Expert verified
The solution to the system is \(x = -0.2\). As all y-values satisfy the second equation (0 = 0), y can be any real number.

Step by step solution

01

Convert the system of equations into a matrix

List all of the coefficients of the variables in the same order in the matrix. The matrix will then be \( \left[ \begin{array}{c c | c} 5 & 3 & -1 \\-10 & -6 & 2 \end{array} \right] \)
02

Apply row operations

The first row operation that will be applied will be Row 2 + 2*Row 1. This gives us the new matrix \( \left[ \begin{array}{c c | c} 5 & 3 & -1 \\-0 & 0 & 0 \end{array} \right] \)
03

Simplify and solve the system

Now we can simplify the matrix by dividing the first row by 5. This gives us the matrix \( \left[ \begin{array}{c c | c} 1 & 0.6 & -0.2 \\-0 & 0 & 0 \end{array} \right] \) This matrix corresponds to the system: \(x + 0.6y = -0.2\) and the second equation is 0 = 0, which gives no new information. To find the value of \(x\), assume \(y=0\), which gives us \(x = -0.2/1 = -0.2\)

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Key Concepts

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

Matrices
Matrices are fundamental tools in linear algebra, especially useful in solving systems of equations. Think of a matrix as a grid that organizes numbers systematically. Each number within the grid is called an element. In the context of solving equations, matrices help simplify and organize complex information.

For our system of equations, the matrix setup captures the coefficients of each variable neatly. For example, if we have equations involving variables like \(x\) and \(y\), the matrix will include their coefficients in a structured format. This matrix makes it easier to apply operations and solve for the variables involved in the original system.
Row Operations
Row operations are steps you perform on a matrix to simplify it or transform it into a more convenient form. These operations are crucial for solving systems of equations using matrices. They include:
  • Swapping two rows.
  • Multiplying a row by a non-zero constant.
  • Adding or subtracting a multiple of one row from another.
Row operations help clear variables from equations or simplify them, making it possible to isolate variables and find their values. Perform these operations carefully to maintain the integrity of the system of equations. For example, in our solution, we performed Row 2 + 2*Row 1 to help eliminate variables from the second row.
Matrix Simplification
Once row operations have been applied, the next step is matrix simplification. This involves converting the matrix into a simpler system, often leading it to what's called row-echelon form. Simplification efforts are aimed at reducing the complexity of the equations, often transforming them into a format where back substitution can be used efficiently.

In our solution's context, matrix simplification involved dividing the first row by 5. This step helped isolate one of the variables, aligning the matrix closer to its simplest form. This simplification prepares us to solve the system effectively and interpret the results with ease.
Systems of Equations
Solving systems of equations means finding values for variables that satisfy all equations in the system simultaneously. These systems can be linear, involving straight-line relationships among variables, or nonlinear.

For linear systems such as our example, matrix methods simplify and expedite the process. By representing the system within a matrix, it becomes easier to manipulate and solve using systematic steps. The goal is always to find a solution where all the given equations hold true. In the exercise, the system was solved after transforming it using matrices and operations, producing solutions that satisfy the original equations.
Linear Algebra
Linear algebra is a branch of mathematics concerned with vectors, matrices, and linear transformations. It provides powerful techniques for solving systems of equations and analyzing linear relationships.

Within linear algebra, matrices serve as key tools for organizing and manipulating data. Understanding the principles of linear algebra ensures students can handle complex systems with ease. It plays a crucial role in fields like engineering, physics, computer science, and more.

Using the concepts and methods from linear algebra, such as the matrix method used in our solution, provides structured pathways to solving equations efficiently, making it an essential part of mathematical learning.

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Most popular questions from this chapter

A couple has \(\$ 10,000\) to invest for their child's wedding. Their accountant recommends placing at least \(\$ 6000\) in a high-yield investment and no more than \(\$ 4000\) in a low-yield investment. (a) Use \(x\) to denote the amount of money placed into the high-yield investment. Use \(y\) to denote the amount of money placed into the low-yield investment. Write a system of linear inequalities that describes the possible amounts the couple could invest in each type of venture. (b) Graph the region that represents all possible amounts the couple could put into each investment if they wish to follow the accountant's advice.

A golf club manufacturer makes a profit of \(\$ 3\) on a driver and a profit of \(\$ 2\) on a putter. To meet dealer demand, the company needs to produce between 20 and 50 drivers and between 30 and 50 putters each day. The maximum number of clubs produced each day by the company is 80. How many of each type of club should be produced to maximize profit?

In this set of exercises, you will use the method of solving linear systems using matrices to study real-world problems. Electrical Engineering An electrical circuit consists of three resistors connected in series. The formula for the total resistance \(R\) is given by \(R=R_{1}+R_{2}+R_{3},\) where \(R_{1}, R_{2},\) and \(R_{3}\) are the resistances of the individual resistors. In a circuit with two resistors \(A\) and \(B\) connected in series, the total resistance is 60 ohms. The total resistance when \(B\) and \(C\) are connected in series is 100 ohms. The sum of the resistances of \(B\) and \(C\) is 2.5 times the resistance of \(A\). Find the resistances of \(A, B\), and \(C\).

Show that \(A+B=B+A\) for any two matrices \(A\) and \(B\) for which addition is defined.

The sum of the squares of two positive integers is \(85 .\) If the squares of the integers differ by 13 find the integers.

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