Identify the y-intercept, then find another point that lies on the grid.
y=- 2/3x+5
Practice makes perfect
Equations written in slope-intercept form follow a specific format.
y= mx+ b
In this form, m is the slope and b is the y-intercept. We need to identify these values using the graph.
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, 5). This means that the value of b is 5.
y= mx+ 5
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 can identify the slope m using the rise and run of the graph.
Here we've identified (3,3) as our other point. Traveling to this point from the y-intercept requires that we move 3 steps horizontally in the positive direction and 2 steps vertically in the negative direction.
rise/run=-2/3 ⇔ m= - 2/3
Writing the Equation
Now that we have the slope and the y-intercept, we can form our final equation.
y= - 2/3x+ 5
