Identify the y-intercept. Use the two given points to calculate the slope.
y=-4/3x+0, or y=-4/3x
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 and the two given points.
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, 0). This means that the value of b is 0.
y= mx+ 0 ⇔ y= mx
Slope
To find the slope, we will consider the two given points and identify the slope m using the rise and run of the graph.
Here we have (-3,4) as our other given point. Traveling from the y-intercept to this point requires that we move 3 steps horizontally in the negative direction and 4 steps vertically in the positive direction.
rise/run=4/-3 ⇔ m= -4/3
Writing the Equation
Now that we have the slope and the y-intercept, we can write our final equation.
y= -4/3x+ 0 or y= -4/3x
