Identify the y-intercept. Use the two given points to calculate the slope.
y=2x-2
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, -2). This means that the value of b is -2.
y= mx+ -2
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 (2,2) as our other given point. Traveling to this point from the y-intercept requires that we move 2 steps horizontally in the positive direction and 4 steps vertically in the positive direction.
rise/run=4/2 ⇔ m= 2
Writing the Equation
Now that we have the slope and the y-intercept, we can write our final equation.
y= 2x+( -2) ⇒ y=2x-2
