/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 18 Solve each system by the additio... [FREE SOLUTION] | 91Ó°ÊÓ

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Solve each system by the addition method. \(\left\\{\begin{array}{l}y--\frac{1}{2} x+2 \\ y-\frac{3}{4} x+7\end{array}\right.\)

Short Answer

Expert verified
The solution to the system of equations is \(x = 20\) and \(y = 12\).

Step by step solution

01

Set up the Addition

The goal is to either add or subtract the equations to get one equation with one variable. We need to get either \(x\) or \(y\) to cancel out when the equations are added together. In this case, we see that \(y\) already has the same coefficient in both equations, so we choose to subtract the second equation from the first one.
02

Subtract the Equations

Subtracting the second equation \(y - \frac{3}{4}x + 7\) from the first equation \(y - \frac{1}{2}x + 2\) generates the following equation: \[ \frac{1}{4}x - 5 = 0 \].
03

Solve for x

Since our goal is to get \(x\) by itself on one side of the equation, we start by adding 5 to both sides to get rid of the -5 on the left side: \[ \frac{1}{4}x = 5 \], Then we multiply both sides by 4 to solve for \(x\), which gives us \(x = 20\).
04

Substitute x into Either Original Equation to Solve for y

Now that we know that \(x = 20\), we can substitute this into either of our original equations to find \(y\). Substituting into the first equation, we get: \(y = \frac{1}{2} * 20 + 2\), which simplifies to \(y = 12\).
05

Check the Solution

The final step is to check the solution \((x = 20,\, y = 12)\) by substituting these values back into both original equations to verify that both equations are true.

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Key Concepts

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

System of Linear Equations
A system of linear equations consists of two or more algebraic equations with the same variables. In this particular instance, the system includes the equations
\( y - \frac{1}{2}x + 2 = 0 \) and \( y - \frac{3}{4}x + 7 = 0 \). The objective is to find the values of \( x \) and \( y \) that satisfy both equations simultaneously. These values represent the point where the two lines, if graphed, would intersect. Solving a system like this can be done using several methods, including graphing, substitution, elimination (also known as the addition method), and matrix approaches.
Algebraic Methods
Algebraic methods refer to a suite of techniques used to solve equations. These include but are not limited to the substitution method, the addition or elimination method, and the multiplication method. Each technique has its advantages and is suitable for different kinds of systems. When choosing an algebraic method, one should consider which offers the most straightforward path to the solution. In the context of our example, the addition method is selected because it leads to a quick elimination of one of the variables, paving the way for an easier solution.
Substitution Method
The substitution method is one of the algebraic techniques used to solve systems of linear equations. This method involves solving one of the equations for a particular variable and then substituting that expression into the other equation(s). The goal is to reduce the system to a single equation with one variable. However, for the given exercise, the substitution method was not utilized as the primary strategy. Instead, the addition method was chosen due to the setup of the coefficients, which allowed for quicker variable elimination.
Equation Solving
Solving equations entails manipulating the given algebraic expressions to determine the values of the unknown variables. It involves a series of logical steps: isolation of variables, simplification, and verification. After isolating the variable \( x \) through the addition method in our example, we simplified the resulting equation to find \( x = 20 \). Subsequently, by substituting this value back into one of the original equations, we obtained \( y = 12 \). Lastly, the solution pair \( (x = 20, y = 12) \) was verified by ensuring it met the conditions of both initial equations, confirming its accuracy. Such procedural rigor is key to solving equations and anchoring the understanding of algebraic concepts.

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Most popular questions from this chapter

In Exercises 29-32, determine whether each statement makes sense or does not make sense, and explain your reasoning. In order to solve a linear programming problem, I use the graph representing the constraints and the graph of the objective function.

Involve supply and demand. The following models describe wages for low-skilled labor. \(\begin{array}{lcc}\text { Demand Model } & \text { Supply Model } \\ p-- 0.325 x+5.8 & p-0.375 x+3\end{array}\) a. Solve the system and find the equilibrium number of workers, in millions, and the equilibrium hourly wage. b. Use your answer from part (a) to complete this statement: If workers are paid ___ per hour, there will be ___ million available workers and ___ millions workers will be hired. c. In 2007 , the federal minimum wage was set at \(\$ 5.15\) per hour. Substitute 5.15 for \(p\) in the demand model, \(p--0.325 x+5.8,\) and determine the millions of workers employers will hire at this price. d. At a minimum wage of \(\$ 5.15\) per hour, use the supply model, \(p-0.375 x+3,\) to determine the millions of available workers. Round to one decimal place. e. At a minimum wage of \(\$ 5.15\) per hour, use your answers from parts (c) and (d) to determine how many more people are looking for work than employers are willing to hire.

This will help you prepare for the material covered in the next section. In each exercise, graph the linear function. $$f(x)=-\frac{2}{3} x$$

The graphs of solution sets of systems of inequalities involve finding the intersection of the solution sets of two or more inequalities. By contrast, in Exercises \(71-72,\) you will be graphing the union of the solution sets of two inequalities. Graph the union of \(x-y \geq-1\) and \(5 x-2 y \leq 10\).

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