Identify the y-intercept. Then, find another point that lies on the grid.
C
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.
Finding the y-intercept
Observe the given graph.
We can see that the function intercepts the y-axis at (0,1). This means that the value of b is 1.
Finding the Slope
To find the slope, we will trace along the line on the given graph until we find a lattice point, which is a point that lies perfectly on the grid lines. Doing so, we will be able to identify the slope m using the rise and run of the graph.
Here we have identified the x-intercept at (-1,-1) as our other point. Traveling to this point from the y-intercept requires that we move 1 step horizontally in the negative direction and 2 steps vertically in the negative direction.
rise/run=-2/-1 ⇔ m= 2
Writing the Equation
Now that we have the slope and the y-intercept, we can form our final equation.
y= mx+b
y= 2x+1
Therefore, C is the correct answer.
