Chapter 4: Problem 21
Solve each system of linear equations by graphing. See Examples 3 through \(6 .\) \(\left\\{\begin{array}{l}x+y=5 \\ x+y=6\end{array}\right.\)
Short Answer
Expert verified
The system has no solution because the lines are parallel and do not intersect.
Step by step solution
01
Understand the System of Equations
We have a system of two linear equations: \(x + y = 5\) and \(x + y = 6\). Both are linear equations in two variables.
02
Convert Equations into Slope-Intercept Form
Each equation can be written in the form \(y = mx + b\). For \(x + y = 5\), we subtract \(x\) from both sides to get \(y = -x + 5\). For \(x + y = 6\), we also subtract \(x\) from both sides, resulting in \(y = -x + 6\).
03
Graph the Equations
Graph both equations on the same coordinate plane. The first line \(y = -x + 5\) has a y-intercept at \(5\) and a slope of \(-1\), so you go down 1 unit and right 1 unit from the y-intercept. The second line \(y = -x + 6\) has a y-intercept at \(6\) and the same slope of \(-1\), so you again go down 1 unit and right 1 unit from the y-intercept.
04
Interpret the Intersection
Observe where the two lines intersect. In this case, since both lines are parallel (same slope but different y-intercepts), they do not intersect anywhere on the plane.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing Linear Equations
Graphing linear equations involves plotting a line on a coordinate plane. This line represents all solutions to the equation. When graphing the equation, you need to identify two key components: the slope and the y-intercept.
To graph the equation effectively:
To graph the equation effectively:
- Begin by identifying the y-intercept, the point where the line crosses the y-axis. For example, in equations like \(y = -x + 5\), the y-intercept is \(5\).
- Then, use the slope (in this case, \(-1\)) to determine direction and steepness. The slope tells us how to move from the y-intercept to another point on the line.
Parallel Lines
Parallel lines are lines in a plane that never meet. They have the same slope but different y-intercepts. Understanding parallel lines is crucial in solving systems of equations.
A system of equations can result in parallel lines when the equations have:
A system of equations can result in parallel lines when the equations have:
- Identical slopes (ensuring the lines move in the same direction).
- Different y-intercepts (ensuring the lines are apart).
Slope-Intercept Form
The slope-intercept form is a way of writing linear equations as \(y = mx + b\). It clearly displays the slope \(m\) and the y-intercept \(b\) of the line.
Key features of the slope-intercept form:
Key features of the slope-intercept form:
- The slope \(m\) represents the line's direction and steepness. A positive slope rises as it moves from left to right; a negative slope falls.
- The y-intercept \(b\) is where the line crosses the y-axis. This is your starting point on the graph.
Intersection of Lines
The intersection of lines on a graph represents the solution to a system of linear equations. It's the point where the lines cross, which corresponds to values that satisfy both equations simultaneously.
When graphing two lines, several outcomes are possible:
When graphing two lines, several outcomes are possible:
- If the lines intersect at a single point, that point is the solution to the system.
- If the lines are parallel, as in our example \(x + y = 5\) and \(x + y = 6\), no intersection occurs, indicating no solution to the system.
- If the lines coincide (completely overlap), the system has infinitely many solutions, as any point on the line satisfies both equations.