Chapter 2: Problem 52
Use a graphing calculator to graph each equation, and then find the \(x\) -coordinate of the \(x\) -intercept to the nearest hundredth. Determining the \(x\) -intercepts of a Graph. \(0.3 x+y=7.5\)
Short Answer
Expert verified
The x-intercept is at x = 25.
Step by step solution
01
Rewrite the Equation in Slope-Intercept Form
Start by rewriting the equation in the form of \(y = mx + b\), which is the slope-intercept form. The given equation is \(0.3x + y = 7.5\). Subtract \(0.3x\) from both sides to isolate \(y\), getting \(y = -0.3x + 7.5\).
02
Understand the Concept of x-Intercept
The \(x\)-intercept is the point where the graph of the equation crosses the \(x\)-axis. At this point, the value of \(y\) is zero. Therefore, to find the \(x\)-intercept, set \(y = 0\) in the equation and solve for \(x\).
03
Solve for the x-Intercept
Using the equation \(y = -0.3x + 7.5\), set \(y = 0\) to find the \(x\)-intercept: \(0 = -0.3x + 7.5\). Solving for \(x\), we add \(0.3x\) to both sides: \(0.3x = 7.5\).Divide both sides by \(0.3\): \(x = \frac{7.5}{0.3} = 25\).
04
Graph the Equation using a Graphing Calculator
Enter the equation \(y = -0.3x + 7.5\) into the graphing calculator. Look at the graph to confirm that it intersects the \(x\)-axis at \(x = 25\). This visual confirmation ensures that our calculations are correct.
05
Verify the x-Intercept Value
To ensure accuracy, re-evaluate the calculations and check the graph's intersection with the \(x\)-axis. Our calculation shows the correct x-intercept at \(x = 25\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Using a Graphing Calculator Effectively
A graphing calculator is a powerful tool that can help visualize the relationship in a linear equation. It is especially useful when you want to find the x-intercept of a graph. To use it effectively, follow these steps:
- Enter the equation in the format the calculator accepts, often in slope-intercept form.
- Make sure the window settings are appropriate so that the x-axis and y-axis are clearly visible.
- Graph the equation and observe where the line crosses the x-axis. This point is your x-intercept.
Understanding Slope-Intercept Form
The slope-intercept form of a linear equation is one of the most straightforward forms to use, expressed as \( y = mx + b \). Here, \( m \) represents the slope, and \( b \) is the y-intercept. Let's break this down further:
- Slope \( m \): This indicates the steepness of the line and the direction it goes. A positive slope means the line rises as it moves from left to right, while a negative slope means it falls.
- Y-intercept \( b \): The y-intercept is where the line crosses the y-axis. This tells us the starting point of the line when \( x = 0 \).
Solving Linear Equations for the x-Intercept
Knowing how to find the x-intercept of a linear equation is crucial, especially in various applications like physics or economics. Here's how you solve for the x-intercept, step-by-step:
- Start with the equation in slope-intercept form, \( y = mx + b \).
- Set \( y = 0 \) because the x-intercept is where the line crosses the x-axis, and at this point, \( y \) is always zero.
- Solve for \( x \):
- Use algebraic steps to isolate \( x \), first by eliminating any constants or coefficients from one side.
- Simplify the equation to solve for \( x \), providing the exact location of the x-intercept on the graph.