Chapter 10: Problem 29
In Exercises 29 to \(34,\) draw the line described. Through \((3,-2)\) and with \(m=2\)
Short Answer
Expert verified
The line is given by the equation \( y = 2x - 8 \). Draw it by using the y-intercept at \(-8\) and slope \(2\).
Step by step solution
01
Understand the Problem Statement
We are asked to draw a line that passes through the point \((3, -2)\) and has a slope \(m = 2\). The equation of a line we often use for such a situation is the point-slope form, \(y - y_1 = m(x - x_1)\), where \(m\) is the slope and \((x_1, y_1)\) is the point the line goes through.
02
Substitute Values into the Point-Slope Formula
Using the point-slope form of the line equation, substitute \(x_1 = 3\), \(y_1 = -2\), and \(m = 2\) into the equation: \[ y - (-2) = 2(x - 3) \]Simplify the equation to make it ready for further processing:\[ y + 2 = 2(x - 3) \].
03
Simplify the Equation
Expand the equation further by applying the distributive property:\[ y + 2 = 2x - 6 \].Next, isolate the variable \(y\) by subtracting 2 from both sides:\[ y = 2x - 6 - 2 \].So the equation simplifies to:\[ y = 2x - 8 \].
04
Draw the Line on a Graph
Now that we have the equation \(y = 2x - 8\), use it to draw the line. Start by plotting the point where the line intersects the y-axis (the y-intercept), which is \(-8\). From this point, use the slope to find another point: rise 2 units up and run 1 unit to the right from the y-intercept to find another point on the line. Connect these points with a straight line.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Point-Slope Form
In geometry, when we talk about the equation of a line, one very common form is the "point-slope" form. The point-slope form is super useful because it helps us quickly write down the equation of a line if we know two pieces of information: a point the line passes through and the slope of the line.
The formula for the point-slope form is:
The formula for the point-slope form is:
- \( y - y_1 = m(x - x_1) \)
- \((x_1, y_1)\) is a point on the line, and
- \(m\) is the slope of the line.
- Plug in the values of the known point into \((x_1, y_1)\).
- Use the given slope \(m\).
- Simplify to find the line's equation.
Equation of a Line
Equations of lines are like the recipes for drawing lines on a graph. In this context, the equation we derived was \( y = 2x - 8 \). This is in the slope-intercept form, where equations are written as \( y = mx + b \).
Here:
Here:
- \(m\) is the slope (how steep the line is).
- \(b\) is where the line hits, or intersects, the y-axis, also known as the y-intercept.
Graphing Lines
Graphing lines can be a fun and rewarding task once you understand how the equations work. To graph the line represented by \( y = 2x - 8 \), you simply follow the steps:
- Start by locating the y-intercept on the y-axis. Here, the y-intercept is \(-8\), so you begin there.
- Use the slope to find additional points. For every unit you move to the right (positive direction along the x-axis), move 2 units up because the slope \(m = 2\) means rise over run is 2 over 1.
- Mark these points on the graph.
- Connect the dots to form a straight line.
Slope
Slope is a core concept in understanding lines in geometry. It tells us how slanted or steep a line is. The slope \(m\) measures how fast \(y\) changes with \(x\).
Visually, slope is seen as:
Visually, slope is seen as:
- "rise over run," which means how many units you go up or down (rise) for every unit you go right or left (run).
- A positive slope, like our \(m = 2\), suggests the line rises as we move from left to right.
- A negative slope would mean the line falls as we move from left to right.
- If the slope is zero, the line is perfectly horizontal.
- If the slope is undefined (which happens when the run is zero), the line is vertical.