Graphing Equations Quick Check

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Question
Use the image to answer the question.
A coordinate plane shows the x-axis ranging from negative 9 to 9 in increments of 1 and the y-axis ranging from 11 to negative 11 in increments of 1. A line with arrows at both ends joins two plotted points.
The coordinates of the plotted points are as follows: left parenthesis 0 comma 3 right parenthesis, and left parenthesis 3 comma 2 right parenthesis.
Is this the correct graph of y=−13x+4
?(1 point)
Responses

Yes, it is the correct graph because this graph has a y
-intercept of (0,4)
.
Yes, it is the correct graph because this graph has a y -intercept of left parenthesis 0 comma 4 right parenthesis .

Yes, it is the correct graph because this graph has a y
-intercept of (0,3)
.
Yes, it is the correct graph because this graph has a y -intercept of left parenthesis 0 comma 3 right parenthesis .

No, it is not the correct graph because this graph has a positive slope.
No, it is not the correct graph because this graph has a positive slope.

No, it is not the correct graph because this graph used (0,3)
as the y
-intercept.

1 answer

To determine if the graph correctly represents the equation \( y = -\frac{1}{3}x + 4 \), we need to analyze its y-intercept and slope.

  1. Y-intercept: The y-intercept of the equation \( y = -\frac{1}{3}x + 4 \) is the point where \( x = 0 \). Substituting \( x = 0 \):

    \[ y = -\frac{1}{3}(0) + 4 = 4 \]

    So, the y-intercept is \( (0, 4) \).

  2. Slope: The slope of the equation \( y = -\frac{1}{3}x + 4 \) is \( -\frac{1}{3} \), which is negative, meaning the line should decrease as it moves from left to right.

Now, comparing this information to the plotted points provided:

  • The graph shows points \( (0, 3) \) and \( (3, 2) \).

For the point \( (0, 3) \):

  • At \( x = 0 \), the graph shows \( y = 3 \), not \( y = 4 \). This is a discrepancy since the correct y-intercept should be \( (0, 4) \).

For the slope calculation:

  • The slope from point \( (0, 3) \) to point \( (3, 2) \) is:

\[ \text{slope} = \frac{2 - 3}{3 - 0} = \frac{-1}{3} \]

This slope is negative, which is consistent with the expected behavior of the line.

Final Assessment:

  • The correct y-intercept for the line \( y = -\frac{1}{3}x + 4 \) is \( (0, 4) \), but the graph shows the y-intercept as \( (0, 3) \), which is incorrect.

Correct Answer: No, it is not the correct graph because this graph used \( (0, 3) \) as the y-intercept.