Given the conditions of the function, we can derive its equation based on the information provided:
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Initial Value (y-intercept): The function has an initial value of −1, which means the y-intercept (\(b\)) is \(-1\). Therefore, when \(x=0\), \(y=-1\).
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Slope: The slope (\(m\)) is given as \(3\). This indicates that for every unit increase in \(x\), \(y\) increases by \(3\).
From this, we can construct the equation of the line in the slope-intercept form:
\[ y = mx + b \] \[ y = 3x - 1 \]
Finding the Intercepts
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Y-Intercept: As mentioned, when \(x = 0\), \(y = -1\). Therefore, the line intersects the y-axis at the point \((0, -1)\).
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X-Intercept: To find the x-intercept (\(y=0\)): \[ 0 = 3x - 1 \] \[ 3x = 1 \] \[ x = \frac{1}{3} \] So, the x-intercept is \(\left(\frac{1}{3}, 0\right)\).
Qualitative Features
- The function is a linear function that slopes upwards with a positive slope (3).
- It intersects the y-axis at the point (0, -1) and has a small positive x-intercept around \(0.33\).
Based on these criteria, the correct sketch of the graph should include:
- An upward line passing through the point (0, -1) on the y-axis.
- The x-intercept around \(\frac{1}{3}\), indicating where the line crosses the x-axis.
- The line will reside primarily in the first quadrant, but it will also cover parts of the fourth and third quadrants due to its upward slope.
Choosing the Correct Sketch
Among the sketches described:
- The one that matches these details is:
- An upward line with the correct intersection points for the x-axis and y-axis.
So, the correct option from the choices provided is the image showing a line intersecting the y-axis at (0, -1) and the x-axis at approximately (0.33, 0).