Chapter 2: Problem 54
Find the intercepts. Then graph by using the intercepts, if possible, and a third point as a check. $$ 5 x-4 y=20 $$
Short Answer
Expert verified
The x-intercept is (4, 0) and the y-intercept is (0, -5). A third point is (2, -2.5).
Step by step solution
01
Find the x-intercept
To find the x-intercept, set y = 0en the equation and solve for x: 5x - 4(0) = 20 This simplifies to 5x = 20 Divide both sides by 5: x = 4 So, the x-intercept is (4, 0).
02
Find the y-intercept
To find the y-intercept, set x = 0en the equation and solve for y: 5(0) - 4y = 20 This simplifies to -4y = 20 Divide both sides by -4: y = -5So, the y-intercept is (0, -5).
03
Find a third point as a check
Choose another value for x to find a third point. Let’s choose x = 2.Substitute x = 2 into the equation: 5(2) - 4y = 20This simplifies to 10 - 4y = 20Subtract 10 from both sides: -4y = 10Divide both sides by -4: y = -2.5So, the third point is (2, -2.5).
04
Graph the intercepts and the third point
Plot the points (4, 0), (0, -5), and (2, -2.5) on the coordinate plane. Draw a line through these points to graph the equation. Verify that all points lie on the same straight line.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
x-intercept
The x-intercept of an equation is the point where the graph crosses the x-axis. This means the y-coordinate is 0 at this point. To find the x-intercept of a linear equation like 5x - 4y = 20, we set y to 0 and solve for x.
Here's the process:
Here's the process:
- Substitute y = 0 into the equation: 5x - 4(0) = 20.
- This simplifies to 5x = 20.
- Divide both sides by 5 to solve for x: x = 4.
y-intercept
The y-intercept is the point where the graph crosses the y-axis. At this point, the x-coordinate is 0. To find the y-intercept of the equation 5x - 4y = 20, we set x to 0 and solve for y.
Here’s how to find it:
Here’s how to find it:
- Substitute x = 0 into the equation: 5(0) - 4y = 20.
- This simplifies to -4y = 20.
- Divide both sides by -4 to solve for y: y = -5.
graphing linear equations
Graphing linear equations involves plotting points on the coordinate plane and drawing a straight line through them. For the equation 5x - 4y = 20, we have already found the intercepts:
- x-intercept: (4, 0)
- y-intercept: (0, -5)
- Substitute x = 2 into the equation: 5(2) - 4y = 20.
- This simplifies to 10 - 4y = 20.
- Solve for y: -4y = 10; y = -2.5.
solving linear equations
Solving linear equations involves finding the values of variables that make the equation true. In the context of finding intercepts, we’re looking for x and y values where the graph crosses the axes.
For x-intercept:
For x-intercept:
- Set y = 0 and solve for x.
- In our example, 5x = 20 means x = 4.
- Set x = 0 and solve for y.
- In our example, -4y = 20 means y = -5.
coordinate plane
The coordinate plane is a two-dimensional surface where we can plot points, lines, and curves. It is divided into four quadrants by the x-axis and y-axis. Each point on the plane is represented by an ordered pair (x, y).
For example, the point (4, 0) means:
For example, the point (4, 0) means:
- 4 units to the right of the origin on the x-axis.
- 0 units up or down on the y-axis.
- 0 units to the right or left on the x-axis.
- 5 units down on the y-axis.