Chapter 3: Problem 40
Find the \(x\) - and \(y\) -intercepts. Then graph each equation. $$ 3 x-7 y=9 $$
Short Answer
Expert verified
x-intercept: 3, y-intercept: -\frac{9}{7}.
Step by step solution
01
- Find the x-intercept
To find the x-intercept, set y to 0 and solve for x: \(3x - 7(0) = 9 \) \(3x = 9 \) \(x = \frac{9}{3} \) \(x = 3.\)
02
- Find the y-intercept
To find the y-intercept, set x to 0 and solve for y: \(3(0) - 7y = 9\) \(-7y = 9 \) \(y = \frac{9}{-7} \) \(y = -\frac{9}{7}.\)
03
- Plot the intercepts
Plot the x-intercept (3, 0) and the y-intercept (0, \(-\frac{9}{7}\)) on a coordinate plane.
04
- Draw the line
Draw a straight line passing through the points (3, 0) and (0, \(-\frac{9}{7}\)). This line represents the equation 3x - 7y = 9.
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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 a linear equation is the point where the graph crosses the x-axis. This happens when the y-coordinate is zero. To find the x-intercept for the equation given in the exercise, follow these steps:
Set y to 0 in the equation:
$$3x - 7(0) = 9$$
Simplify the equation:
$$3x = 9$$
Solve for x by dividing both sides by 3:
$$x = \frac{9}{3}$$
$$x = 3$$
So, the x-intercept is the point (3, 0). This is where the graph will intersect the x-axis.
Set y to 0 in the equation:
$$3x - 7(0) = 9$$
Simplify the equation:
$$3x = 9$$
Solve for x by dividing both sides by 3:
$$x = \frac{9}{3}$$
$$x = 3$$
So, the x-intercept is the point (3, 0). This is where the graph will intersect the x-axis.
y-intercept
The y-intercept is the point where the graph crosses the y-axis. This happens when the x-coordinate is zero. To find the y-intercept for the equation given in the exercise, follow these steps:
Set x to 0 in the equation:
$$3(0) - 7y = 9$$
Simplify the equation:
$$-7y = 9$$
Solve for y by dividing both sides by -7:
$$y = \frac{9}{-7}$$
$$y = -\frac{9}{7}$$
So, the y-intercept is the point (0, -9/7). This is where the graph will intersect the y-axis.
Set x to 0 in the equation:
$$3(0) - 7y = 9$$
Simplify the equation:
$$-7y = 9$$
Solve for y by dividing both sides by -7:
$$y = \frac{9}{-7}$$
$$y = -\frac{9}{7}$$
So, the y-intercept is the point (0, -9/7). This is where the graph will intersect the y-axis.
coordinate plane
The coordinate plane is a two-dimensional surface used for graphing equations. It consists of two perpendicular number lines: the x-axis (horizontal) and the y-axis (vertical). These axes intersect at the origin (0,0). Each point on the plane can be described by a pair of numbers, known as coordinates, which are written as (x, y). To plot points on a coordinate plane:
In the exercise, we plot the x-intercept (3, 0) and the y-intercept (0, -9/7) on the coordinate plane, and draw a line through these points to graph the equation.
- Find the x-coordinate and move along the x-axis to that value.
- Find the y-coordinate and move along the y-axis to that value.
- The intersection of these two values is the point's location.
In the exercise, we plot the x-intercept (3, 0) and the y-intercept (0, -9/7) on the coordinate plane, and draw a line through these points to graph the equation.
linear equations
A linear equation is an algebraic equation in which each term is either a constant or the product of a constant and a single variable. They can be written in the form Ax + By = C, where A, B, and C are constants. Linear equations graph as straight lines, and their solutions are all the points on these lines.
In the exercise, we started with the linear equation 3x - 7y = 9. By finding the x- and y-intercepts, we identified two points that lie on the graph. Here's a recap:
This process effectively graphs any linear equation, letting us visually represent solutions.
In the exercise, we started with the linear equation 3x - 7y = 9. By finding the x- and y-intercepts, we identified two points that lie on the graph. Here's a recap:
- Find where the line crosses the x-axis (x-intercept by setting y to 0).
- Find where the line crosses the y-axis (y-intercept by setting x to 0).
- Plot these intercepts on the coordinate plane and draw a line through them.
This process effectively graphs any linear equation, letting us visually represent solutions.