Chapter 3: Problem 52
Find an equation of each line described. Write each equation in slope- intercept form when possible. Through (4,7) and (0,0)
Short Answer
Expert verified
The equation of the line is \( y = \frac{7}{4}x \).
Step by step solution
01
Understanding the Problem
We need to find the equation of a line that passes through the points (4,7) and (0,0), and express the equation in slope-intercept form, if possible.
02
Finding the Slope
Calculate the slope of the line using the formula for the slope \( m = \frac{y_2 - y_1}{x_2 - x_1} \). Here, \( (x_1, y_1) = (4, 7) \) and \( (x_2, y_2) = (0, 0) \). Substitute these into the formula: \( m = \frac{0 - 7}{0 - 4} = \frac{-7}{-4} = \frac{7}{4} \).
03
Using Point-Slope Form
Once we have the slope \( m = \frac{7}{4} \), use the point-slope form of the equation: \( y - y_1 = m(x - x_1) \). Substitute \( m \), \( x_1 = 4 \), and \( y_1 = 7 \) into the equation: \( y - 7 = \frac{7}{4}(x - 4) \).
04
Converting to Slope-Intercept Form
The equation from the previous step is \( y - 7 = \frac{7}{4}(x - 4) \). Distribute \( \frac{7}{4} \): \( y - 7 = \frac{7}{4}x - 7 \). Add 7 to both sides to solve for \( y \): \( y = \frac{7}{4}x \). This is the slope-intercept form \( y = mx + b \) with \( m = \frac{7}{4} \) and \( b = 0 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Equation of a Line
An equation of a line provides a mathematical representation of a straight line on a coordinate plane. It is essential in algebra and geometry for describing the relationship between any two points along that line.
Generally, the most common form representing the equation of a line is the slope-intercept form, expressed as:
Generally, the most common form representing the equation of a line is the slope-intercept form, expressed as:
- \( y = mx + b \)
- \( y \) is the dependent variable (typically the output).
- \( x \) is the independent variable (typically the input).
- \( m \) represents the slope of the line, which indicates the line's steepness.
- \( b \) is the y-intercept, the point where the line crosses the y-axis.
Slope Calculation
The slope of a line is a measure of its steepness and is represented by the letter \( m \). It tells us how much \( y \) changes for a given change in \( x \).
The formula for calculating the slope between two points \((x_1, y_1)\) and \((x_2, y_2)\) is:
Let's consider an example: to calculate the slope between the points (4, 7) and (0, 0), apply the formula:
The formula for calculating the slope between two points \((x_1, y_1)\) and \((x_2, y_2)\) is:
- \( m = \frac{y_2 - y_1}{x_2 - x_1} \)
Let's consider an example: to calculate the slope between the points (4, 7) and (0, 0), apply the formula:
- \( m = \frac{0 - 7}{0 - 4} = \frac{-7}{-4} = \frac{7}{4} \)
Point-Slope Form
The point-slope form is another way of expressing the equation of a line. It is particularly useful when you know a point on the line and the slope.
The formula for the point-slope form is:
By rearranging the equation, you can transform the line from the point-slope form to the slope-intercept form of \( y = mx + b \). This transformation is crucial when you need to easily identify slope and y-intercept for graphing or further applications.
The formula for the point-slope form is:
- \( y - y_1 = m(x - x_1) \)
- \((x_1, y_1)\) is a known point on the line.
- \( m \) is the slope of the line.
- \( y - 7 = \frac{7}{4}(x - 4) \)
By rearranging the equation, you can transform the line from the point-slope form to the slope-intercept form of \( y = mx + b \). This transformation is crucial when you need to easily identify slope and y-intercept for graphing or further applications.