Verified Answer :
- The equation \(y = -\frac{3}{2}x - 3\) is in slope-intercept form, with slope \(m = -\frac{3}{2}\) and y-intercept \(b = -3\).
- The line passes through the points \((0, -3)\), \((2, -6)\), and \((-2, 0)\).
- Plot these points on the coordinate plane and connect them with a straight line.
- The resulting line represents a constant downward rate of change of 1.5 units per 1 horizontal unit.
Explanation
- Analyzing the Linear Equation
The equation \(y = -\frac{3}{2}x - 3\) represents a linear function in the form \(y = mx + b\), where \(m\) is the slope and \(b\) is the y-intercept. In this case, the slope \(m = -\frac{3}{2}\) and the y-intercept \(b = -3\). The y-intercept indicates that the line passes through the point \((0, -3)\) on the Cartesian coordinate plane.
- Identifying Points on the Line
To graph this line, we need to find at least two points that satisfy the equation. We already have the y-intercept \((0, -3)\). To find another point, we can choose a convenient value for \(x\). Let's pick \(x = 2\). Substituting this into the equation, we get:
\[y = -\frac{3}{2}(2) - 3 = -3 - 3 = -6.\]
So, the point \((2, -6)\) lies on the line. We can also pick \(x = -2\):
\[y = -\frac{3}{2}(-2) - 3 = 3 - 3 = 0.\]
Thus, the point \((-2, 0)\) is also on the line. These three points, \((-2, 0)\), \((0, -3)\), and \((2, -6)\), confirm the trajectory of the line.
- Understanding the Slope
The slope \(m = -\frac{3}{2}\) represents the rate of change of \(y\) with respect to \(x\). It tells us that for every 2 units we move to the right along the x-axis, the line moves 3 units downward. Starting at the y-intercept \((0, -3)\), moving right 2 units brings us to \(x=2\), and moving down 3 units brings us to \(y=-6\), confirming our point \((2, -6)\). This constant slope ensures that the graph is a straight line.
- Drawing the Graph
To draw the graph, plot the points \((-2, 0)\), \((0, -3)\), and \((2, -6)\) on a coordinate system. Using a straight edge, draw a line passing through these points. Since it is a linear function, the line extends infinitely in both directions. The graph displays a downward slope, reflecting the negative value of \(m\). The final visual representation is a straight line crossing the y-axis at \(-3\) and the x-axis at \(-2\).
Examples
Understanding how to graph linear equations is fundamental in various real-life scenarios, such as modeling costs over time or calculating depreciation. For example, if a company's equipment value decreases linearly over time, the equation \(V = -mt + V_0\) can predict the value \(V\) at any time \(t\). Mastering the slope-intercept form allows you to easily visualize these trends and make informed decisions based on the rate at which values change.