We need to find the lien’s equation first. We will use the graph to do so.
We see that the equation is a linear equation as it increases proportionality. Therefore, we can use slope-intercept form: y=mx+b
To find the slope (m), we can either use the slope formula or visually find the rise over run from the two points. Let’s use the graph:
From point (-1, -4) to point (1, 3), the graph rises 1 unit and runs 2 units. Therefore the slope is m=1/2
Now, we must find the y-intercept (b). To do this, we must find the the y value when x=0. When x=0, y=3.5. This is because x=0 means there is no horizontal shift, so it is the input that will derive the y-intercept.
We now have the equation:
y=1/2x-3.5
So, we can evaluate x=3
y=1/2(3)-3.5
y=3/2-3.5
y=1.5-3.5
y=-2
We can check this with the graph, which shows that when x=3, y=-2, thus our answer is correct.