Chapter 2: Problem 50
Find the \(x\) - and \(y\) -intercepts and use them to graph the following functions. $$-8 x+3 y=28$$
Short Answer
Expert verified
The x-intercept is \((-\frac{7}{2}, 0)\) and the y-intercept is \((0, \frac{28}{3})\).
Step by step solution
01
Find the x-intercept
To find the x-intercept, we set the y-value to zero in the equation and solve for x. The given equation is \[-8x + 3y = 28\] Set \(y = 0\): \[-8x + 3(0) = 28\] This simplifies to \[-8x = 28\] Now, solve for x: \[x = \frac{28}{-8}\] \[x = -\frac{7}{2}\] Thus, the x-intercept is \((-\frac{7}{2}, 0)\).
02
Find the y-intercept
To find the y-intercept, we set the x-value to zero in the equation and solve for y. Again using the equation: \[-8x + 3y = 28\] Set \(x = 0\): \[-8(0) + 3y = 28\] This simplifies to: \[3y = 28\] Now, solve for y: \[y = \frac{28}{3}\] Thus, the y-intercept is \((0, \frac{28}{3})\).
03
Plot the intercepts and draw the graph
Using the intercepts calculated in the previous steps, plot the x-intercept \((-\frac{7}{2}, 0)\) and the y-intercept \((0, \frac{28}{3})\) on the coordinate plane. Then draw a straight line through these two points, as they are sufficient to determine the line of the equation.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
x-intercept
The concept of the x-intercept is an essential part of understanding how to graph linear equations. The x-intercept refers to the point at which a line, plotted on a graph, crosses the x-axis.
At this point, the y-coordinate is always zero, as the line is not above or below the x-axis, but exactly on it.
To find the x-intercept for the equation \(-8x + 3y = 28\), we substitute \(y = 0\) and solve for \(x\).
At this point, the y-coordinate is always zero, as the line is not above or below the x-axis, but exactly on it.
To find the x-intercept for the equation \(-8x + 3y = 28\), we substitute \(y = 0\) and solve for \(x\).
- This transforms the equation to \(-8x = 28\)
- Then, solving for \(x\), we get \(x = -\frac{7}{2}\)
y-intercept
The y-intercept is equally important in graphing linear equations. It is the point where the line crosses the y-axis. At this intercept, the x-coordinate is always zero, because the line intersects the y-axis directly.
In our equation, \(-8x + 3y = 28\), we find the y-intercept by setting \(x = 0\) and solving for \(y\).
In our equation, \(-8x + 3y = 28\), we find the y-intercept by setting \(x = 0\) and solving for \(y\).
- This changes the equation to \(3y = 28\)
- Solving gives \(y = \frac{28}{3}\)
coordinate plane
The coordinate plane is a flat, two-dimensional surface that helps us understand the positioning of points defined by a pair of numerical coordinates. These coordinates, expressed in the form \((x, y)\), identify the exact spot for any point on the plane.
When we graph a linear equation, such as \(-8x+3y=28\), the coordinate plane serves as our canvas.
When we graph a linear equation, such as \(-8x+3y=28\), the coordinate plane serves as our canvas.
- The horizontal axis, or x-axis, runs left to right
- The vertical axis, or y-axis, runs top to bottom
plotting points
Plotting points on the coordinate plane involves placing dots at specific locations based on their \((x, y)\) coordinates.
For the equation \(-8x + 3y = 28\), after calculating the \(x\) and \(y\) intercepts, plotting these points gives us a visual guide.
Plotting is a key skill for visually analyzing equations and solutions.It allows us to translate mathematical calculations into clear visual representations.
For the equation \(-8x + 3y = 28\), after calculating the \(x\) and \(y\) intercepts, plotting these points gives us a visual guide.
- The x-intercept \((-\frac{7}{2}, 0)\) tells us where the line crosses the x-axis
- The y-intercept \((0, \frac{28}{3})\) shows where it crosses the y-axis
Plotting is a key skill for visually analyzing equations and solutions.It allows us to translate mathematical calculations into clear visual representations.