Chapter 2: Problem 301
Given the following set of information, find a linear equation satisfying the conditions, if possible. Passes through (5, 1) and (3, –9)
Short Answer
Expert verified
The linear equation is \( y = 5x - 24 \).
Step by step solution
01
Identify Two Points
The problem provides two points through which the line passes: (5, 1) and (3, -9). These points will allow us to calculate the slope and eventually the equation of the line.
02
Calculate the Slope
Use the formula for the slope, which is \( m = \frac{y_2 - y_1}{x_2 - x_1} \). Substituting the given points (5, 1) as \((x_1, y_1)\) and (3, -9) as \((x_2, y_2)\), we get: \[ m = \frac{-9 - 1}{3 - 5} = \frac{-10}{-2} = 5. \] Thus, the slope, \( m \), is 5.
03
Write the Equation in Point-Slope Form
We now use the point-slope form of the equation, \( y - y_1 = m(x - x_1) \), with one of the given points. Using the point (5, 1) and the slope \( m = 5 \), the equation becomes: \[ y - 1 = 5(x - 5). \]
04
Simplify to Slope-Intercept Form
Distribute and simplify the equation from the point-slope form to slope-intercept form, \( y = mx + b \):\[ y - 1 = 5x - 25 \] Add 1 to both sides to solve for \( y \):\[ y = 5x - 25 + 1 \]soy = 5x - 24. Thus, the slope-intercept form of the equation is \( y = 5x - 24 \).
05
Verify the Equation with Second Point
Substitute the second point (3, -9) into the equation \( y = 5x - 24 \) to verify: \[ -9 = 5(3) - 24 \]\[ -9 = 15 - 24 \]\[ -9 = -9 \] Since this statement is true, the equation is correctly fitted to both points.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Slope Calculation
Calculating the slope of a line is a crucial step in formulating a linear equation. The slope tells us how steep a line is and the direction it moves—up or down as we move along the x-axis. To find the slope (\( m \)), you need two points on the line, like the ones given in the problem. The formula for slope is:
Therefore, the slope is 5, indicating that for every one unit increase in x, y increases by 5 units. It is a positive slope, meaning the line rises as it goes from left to right on a graph.
- \( m = \frac{y_2 - y_1}{x_2 - x_1} \)
- \( m = \frac{-9 - 1}{3 - 5} = \frac{-10}{-2} = 5 \)
Therefore, the slope is 5, indicating that for every one unit increase in x, y increases by 5 units. It is a positive slope, meaning the line rises as it goes from left to right on a graph.
Point-Slope Form
The point-slope form is particularly useful when you know a point on the line and the slope. This form is represented as:
This form is useful because it directly incorporates both the slope and a specific point from the line. It provides a straightforward way to see if another point lies on the line by simply plugging it in.
- \( y - y_1 = m(x - x_1) \)
- \( y - 1 = 5(x - 5) \)
This form is useful because it directly incorporates both the slope and a specific point from the line. It provides a straightforward way to see if another point lies on the line by simply plugging it in.
Slope-Intercept Form
When we talk about the slope-intercept form, it's all about making equations easier to understand. Its general format is:
By simplifying it, we convert it to slope-intercept form:
- \( y = mx + b \)
- \( y - 1 = 5(x - 5) \)
By simplifying it, we convert it to slope-intercept form:
- First, distribute the 5: \( y - 1 = 5x - 25 \)
- Then, isolate y by adding 1: \( y = 5x - 24 \)
Verifying Solutions
Verifying a solution involves checking if the equation derived holds true for all the points given. In our example, after forming the equation \( y = 5x - 24 \), we use the second point (3, -9) to ensure it fits the line.
Since the original and calculated values equal each other, the line is confirmed to pass through the point (3, -9). This step reassures you that your equation and calculations are accurate, confirming the line's integrity to represent the given data.
- Substitute \( x = 3 \): \(-9 = 5(3) - 24 \)
- Simplify: \(-9 = 15 - 24 \)
- Results in \(-9 = -9 \)
Since the original and calculated values equal each other, the line is confirmed to pass through the point (3, -9). This step reassures you that your equation and calculations are accurate, confirming the line's integrity to represent the given data.