/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 8 Sketching a Graph by Point Plott... [FREE SOLUTION] | 91Ó°ÊÓ

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Sketching a Graph by Point Plotting In Exercises \(7-16,\) sketch the graph of the equation by point plotting. \(y=5-2 x\)

Short Answer

Expert verified
The graph of the equation \(y=5-2x\) is a straight line that passes through the points (-2, 9), (0, 5), and (2, 1), slanting downwards from left to right.

Step by step solution

01

Identify Key Components of the Equation

The equation \(y = 5 -2x\) has \(m\) = -2 which represents the slope, and \(c\) = 5 which represents the y-intercept.
02

Calculate the Points

Substitute a range of \(x\) values into the equation to calculate corresponding \(y\) values. Let's choose \(x = -2, 0, 2\). When \(x = -2\), \(y= 5 - 2(-2) = 9\). When \(x = 0\), \(y= 5 - 2(0) = 5\). When \(x = 2\), \(y= 5 - 2(2) = 1\). So, the points to plot are (-2, 9), (0, 5), and (2, 1).
03

Plot the Points and Draw the Graph

Plot these points on a graph. Draw a straight line that goes through all the points, since it is a linear function. The line should slope downwards because the slope \(-2\) is negative.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Linear Equations
Understanding linear equations is fundamental to grasping the basics of algebra. A linear equation represents a straight line when plotted on a graph and is typically written in the form of ( y = mx + c ), where ( m ) signifies the slope and ( c ) represents the y-intercept. Essentially, the slope indicates how steep the line is, while the y-intercept tells us where the line crosses the y-axis.

In the case of the equation ( y = 5 - 2x ), the equation is already in this form which makes it easy to identify the slope and y-intercept directly. It’s helpful to note that linear equations are used to model relationships between two variables that have a constant rate of change.
Slope and Y-Intercept
The slope and y-intercept are key aspects of a linear equation. The slope, often denoted as ( m ), measures the rate at which the ( y ) variable changes with respect to the ( x ) variable. A positive slope indicates a line rising from left to right, while a negative slope indicates a line falling from left to right.

On the flip side, the y-intercept, denoted as ( c ), is the point where the graph cuts the y-axis which can be readily seen by setting ( x = 0 ). In the given exercise, the slope is ( m = -2 ), indicating a downward inclined line, and the y-intercept is ( c = 5 ), meaning the line crosses the y-axis at ( y = 5 ).
Plotting Points
Plotting points is a simple yet powerful technique used to sketch graphs of equations. The basic steps involve choosing values for ( x ), then calculating the corresponding ( y ) values using the equation. After calculating, we plot these ( (x, y) ) coordinate pairs on a graph.

To visualize the equation effectively, it's best to select a mixture of positive, negative, and zero for ( x ) values. The plotted points will then provide a visual framework that depicts the behavior of the linear function across the coordinate plane. Joining these points with a straight line unveils the graph of the linear equation.
Linear Functions
Linear functions are mathematical expressions that produce a straight-line graph. They display a constant rate of change and can be quickly identified by their linear equations in the form of ( y = mx + c ). When graphing, the resulting line extends infinitely in both directions but is fully characterized by just two points.

For the ease of understanding and accurate graphing, it is typical to draw at least three points, as small inaccuracies in plotting can lead to an incorrect slope of the graphed line. The consistency in the rate of change means that for equal intervals of increase or decrease in ( x ), the change in ( y ) will always be proportional to the slope. This is why the graph of any linear function will always be a straight line.

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Most popular questions from this chapter

Sketching a Graph of a Function In Exercises \(31-38,\) sketch a graph of the function and find its domain and range. Use a graphing utility to verify your graph. \(f(t)=\frac{2}{7+t}\)

Finding the Domain and Range of a Piecewise Function In Exercises \(27-30\) , evaluate the function at the given value(s) of the independent variable. Then find the domain and range. \(\begin{array}{l}{f(x)=\left\\{\begin{array}{ll}{x^{2}+2,} & {x \leq 1} \\ {2 x^{2}+2,} & {x>1}\end{array}\right.} \\ {\text { (a) } f(-2) \quad \text { (b) } f(0)} & {\text { (c) } f(1)} & {\text { (d) } f\left(s^{2}+2\right)}\end{array}\)

Modeling Data An instructor gives regular 20 -point quizzes and 100 -point exams in a mathematics course. Average scores for six students, given as ordered pairs \((x, y),\) where \(x\) is the average quiz score and \(y\) is the average exam score, are \((18,87),(10,55),(19,96),(16,79),(13,76),\) and \((15,82) .\) (a) Use the regression capabilities of a graphing utility to find the least squares regression line for the data. (b) Use a graphing utility to plot the points and graph the regression line in the same viewing window. (c) Use the regression line to predict the average exam score for a student with an average quiz score of \(17 .\) (d) Interpret the meaning of the slope of the regression line. (e) The instructor adds 4 points to the average exam score of everyone in the class. Describe the changes in the positions of the plotted points and the change in the equation of the line.

Sales The monthly sales \(S\) (in thousands of units) of a seasonal product are modeled by $$S=58.3+32.5 \cos \frac{\pi t}{6}$$ where \(t\) is the time (in months), with \(t=1\) corresponding to January. Use a graphing utility to graph the model for \(S\) and determine the months when sales exceed \(75,000\) units.

Combinations of Functions In Exercises 59 and 60, find (a) \(f(x)+g(x),\) (b) \(f(x)-g(x)\)(c) \(f(x) \cdot g(x),\) and (d) \(f(x) / g(x)\) $$\begin{array}{l}{f(x)=x^{2}+5 x+4} \\ {g(x)=x+1}\end{array}$$

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