Chapter 2: Problem 64
Graph the linear function and label the \(x\) -intercept. $$f(x)=x+3$$
Short Answer
Expert verified
Graph the line through (0, 3) and (-3, 0), with x-intercept at (-3, 0).
Step by step solution
01
Identify the y-intercept
The linear function is given as \(f(x) = x + 3\). This equation is in the slope-intercept form \(y = mx + b\), where \(m\) is the slope and \(b\) is the y-intercept. For this function, the y-intercept \(b\) is 3. This means the graph will cross the y-axis at (0, 3).
02
Identify the slope
In the slope-intercept form \(y = mx + b\), the coefficient \(m\), which is 1 in this case, represents the slope of the line. A slope of 1 means for every unit increase in \(x\), \(y\) increases by 1 unit.
03
Find the x-intercept
The x-intercept is found by setting \(f(x) = 0\) and solving for \(x\). This gives \(0 = x + 3\). Solving for \(x\), we subtract 3 from both sides to get \(x = -3\). So, the x-intercept is at (-3, 0).
04
Plot key points and draw the line
Now, plot the y-intercept (0, 3) on the graph. Also, plot the x-intercept (-3, 0). Use the slope of 1 to add another point by moving 1 unit right and 1 unit up from the y-intercept, reaching (1, 4). Draw a straight line through these points to represent the function.
05
Label the x-intercept on the graph
On the graph you've drawn, clearly label the x-intercept at (-3, 0). This point is where the line crosses the x-axis and represents the solution to \(x + 3 = 0\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing Linear Equations
Graphing a linear equation involves plotting points on a coordinate plane that represent the solutions to the equation. These points line up to form a straight line. Linear equations can be expressed in the form \(y = mx + b\), known as the slope-intercept form. Here, \(m\) is the slope, and \(b\) is the y-intercept. To graph a linear equation, identify these components:
- The y-intercept, where the graph crosses the y-axis, is one of the key points.
- The x-intercept, found by setting \(y = 0\) and solving for \(x\), is another crucial point.
- Plot these intercepts on the cartesian plane to help visualize the line.
x-intercept
The x-intercept of a linear equation is a point where the graph crosses the x-axis. At this point, the value of \(y\) is zero.
To find the x-intercept, set the equation equal to zero and solve for \(x\). For the equation \(f(x) = x + 3\), solve:
To find the x-intercept, set the equation equal to zero and solve for \(x\). For the equation \(f(x) = x + 3\), solve:
- Set \(f(x) = 0\): \(0 = x + 3\).
- Solve for \(x\) by subtracting 3 from both sides: \(x = -3\).
- The x-intercept is \((-3, 0)\).
Slope
A slope is a crucial aspect of a linear equation. It represents the 'steepness' and the direction of the line.
In the slope-intercept form \(y = mx + b\), \(m\) stands for the slope. It shows how much \(y\) changes when \(x\) increases by one unit. If \(m = 1\), like in our function \(f(x) = x + 3\), it means:
In the slope-intercept form \(y = mx + b\), \(m\) stands for the slope. It shows how much \(y\) changes when \(x\) increases by one unit. If \(m = 1\), like in our function \(f(x) = x + 3\), it means:
- For every increase of 1 in \(x\), \(y\) increases by 1.
- The line rises diagonally upward from left to right at an angle of 45 degrees.
- The change is consistent across all points on the line.
Slope-Intercept Form
The slope-intercept form is one way to express a linear equation graphically and algebraically. Expressed as \(y = mx + b\), it provides a clear view of the line's properties:
- \(m\) is the slope: It dictates the direction and angle of the line on the graph.
- \(b\) is the y-intercept: This is where the line crosses the y-axis, at point \((0, b)\).
- Increase \(x\) values to move along the line using the slope.
- The slope helps in finding additional points for more accurate drawing.