Identify the y-intercept, then find another point that lies on the grid.
y=-3/2x
Practice makes perfect
Equations written in Slope-Intercept Form follow a specific format, where m is the slope of the line and b is the y-intercept.
y= mx+b
We need to identify these values using the graph. Let's start with the y-intercept.
Finding the y-intercept
The y-intercept is the y-value where the line crosses the y-axis.
We can see that the function intercepts the y-axis at (0, ). This means that the value of b is .
y= mx+ ⇔ y= mx
Finding the Slope
To find the slope, we will trace along the line on the given graph until we find a lattice point. In doing so, we will be able to identify the slope m using the rise and run of the graph.
Here we've identified (2,-3) as our other point. Traveling to the y-intercept from this point requires that we move 2 steps horizontally in the negative direction and 3 steps vertically in the positive direction.
rise/run=3/-2 ⇔ m= -3/2
Writing the Equation
Now that we have the slope and the y-intercept, we can form our final equation.
y= -3/2x
