Problem 41 - Algebra 1

Question

Use a table of values to graph the equation. \(y=4 x-1\)

Step-by-Step Solution

Answer

The graph of the function \(y=4x-1\) is a straight line that passes through the points (0,-1) and (1, 3).

Step 1: Create a Table of Values

Choose at least two values for x. In this case, let's choose 0 and 1. When \(x=0\), \(y= 4*0 -1 = -1\). When \(x=1\), \(y= 4*1 - 1 = 3\). So, our table of values is: \n (0,-1) and (1, 3)

Step 2: Plot Points on the Graph

Now that we have our table of values, we can plot these points on the graph. Plot the point (0,-1) on the location where x=0 and y=-1. Likewise, plot the point (1,3) where x=1 and y=3.

Step 3: Draw a Line Through the Points

The next step is to draw a line that goes through all the points. This line represents the function in our graph. Since we are dealing with a linear function, our line will be straight.

Key Concepts

Table of Values

Understanding how to create a table of values is essential when graphing linear equations. Think of it as a tool that translates abstract algebraic expressions into concrete numerical pairs that you can easily plot on a graph. To use a table of values for the linear equation \(y = 4x - 1\), we start by selecting input values for \(x\). These values can be any numbers, but it's often convenient to start with simple ones like 0 and 1, as they make the calculations easier.

For each chosen value of \(x\), we must apply the equation to find the corresponding \(y\) value. Let's calculate a few pairs: If we substitute \(x\) with 0, the equation becomes \(y = 4(0) - 1\), which simplifies to \(y = -1\). Thus, our first pair is (0, -1). If we let \(x = 1\), then \(y = 4(1) - 1 = 3\), and the second pair is (1, 3). We now have a set of points that can be plotted on a graph to represent the equation visually.

Plotting Points

Plotting points is like placing anchors on your graph that map out the path of the equation. Each point represents a real-world combination of \(x\) and \(y\) that satisfies the equation \(y = 4x - 1\). To plot the points from our table of values effectively, begin with your axes labeled and marked evenly.

Take the point (0, -1) we calculated earlier; the first number, 0, tells us where to stand on the \(x\)-axis, and the second number, -1, tells us how far to move up or down on the \(y\)-axis. In this case, since our \(x\) value is 0, we start at the origin and move one unit down on the \(y\)-axis. Similarly, for the point (1, 3), we move one unit right from the origin along the \(x\)-axis and then go up 3 units along the \(y\)-axis. Connecting these 'anchors' will help us visualize the equation's behavior.

Linear Function

A linear function is the algebraic equivalent of a straight line on a graph. It's an equation of the first degree, which means none of the variables are raised to a power higher than one. For the function we're working with, \(y = 4x - 1\), the convention follows that \(y\) is the dependent variable which changes in response to the independent variable \(x\).

Important characteristics of a linear function include its slope and y-intercept. The slope describes the steepness of the line, in our case, 4. This indicates that for each step we move to the right on the x-axis, the y-value increases by 4 steps. The y-intercept is the point where the line crosses the y-axis, which occurs when \(x\) is zero. In this equation, the y-intercept is -1. Understanding these concepts allows us to chart the function's course and predict its behavior across the graph.