Chapter 8: Problem 7
Solve each system. $$\left\\{\begin{array}{l} x+y=5 \\ x-y=-1 \end{array}\right.$$
Short Answer
Expert verified
The solution of the system of equations is \(x = 2\) and \(y = 3\).
Step by step solution
01
Add the Two Equations
Given the equations \(x + y = 5\) and \(x - y = -1\). Add the two equations. Ideal for this system as the variable y in the two equations will cancel each other when performing addition.
02
Solve for x
After the addition of the equations in Step 1, the result is \(2x = 4\). To isolate the variable x, divide both sides of the equation by 2. This yields the value of x.
03
Substitute x-value to find y
After finding the value of x, substitute this value into either of the original equations to find the value of y. Choosing the first equation from the system \(x + y = 5\), replacing x with 2 gives \(2 + y = 5\). Solving for y gives us the value of y.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Addition Method
The addition method, also known as the elimination method, is a technique used for solving systems of linear equations. This method can efficiently eliminate one variable and solve for the other. Here's how it works:
- Identify two equations in a system that, when added together, will eliminate one of the variables. This is possible when the coefficients of one variable are opposites. For example, in the system \(x + y = 5\) and \(x - y = -1\), the y-terms \(+y\) and \(-y\) will cancel each other out when added.
- Add the two equations together. For the given system, adding the equations yields \(2x = 4\).
- Solve the resulting equation for the remaining variable. In this case, dividing both sides by 2 will isolate \(x\), resulting in \(x = 2\).
Substitution Method
The substitution method is another way to tackle systems of linear equations, providing a clear path to finding solutions by isolating and substituting variables. To use it effectively, follow these steps:
- Start by solving one of the equations for one variable. This is done by isolating the variable on one side of the equation. For example, from the equation \(x + y = 5\), we can solve for \(y\), resulting in \(y = 5 - x\).
- Substitute this expression into the other equation. Replace \(y\) in the second equation \(x - y = -1\) with \(5 - x\), resulting in \(x - (5 - x) = -1\).
- Simplify and solve for the remaining variable. This operation leads you to \(2x - 5 = -1\), and solving for \(x\) gives \(x = 2\).
- Finally, substitute the value of the solved variable back into the expression from the first step to find the other variable. Here, substituting \(x = 2\) back gives \(y = 3\).
Linear Equations
Linear equations are mathematical statements expressing equality between two expressions involving constants and variables. They represent straight lines when graphed on a coordinate plane. Here's what characterizes them:
- They have no exponents higher than one on any variable. This means equations like \(x + y = 5\) and \(x - y = -1\) are linear because variables are not squared, cubed, or involved in higher powers.
- They can be written in the form \(ax + by = c\), where \(a\), \(b\), and \(c\) are constants. Constants can be any real number, and \(a\) or \(b\) can be zero, but not both at the same time.
- The solutions to linear equations form a line on the graph, indicating infinitely many solutions for a single linear equation. In systems with two equations, finding the point where the two lines intersect solves the system.