Graph with Slope & Y-intercept

Graph with Slope & Y-intercept - How it Works - Video

Example 1

Example 1:

Here we have to graph with the following features: slope = 3 and y-intercept = 1.

We plot the y-intercept first, which is at the point (0, 1). Next we using the slope 3/1 to find the next point. We go up 3 and then to the right 1 since our slope is positive. We should always plot at least 3 points because it will be easier to see if we made a mistake with 3 points. Let's talk about the pictures.

The picture on the left:

We started at the y-intercept, (0, 1), and moved 3 up and 1 to the right. We cannot continue this way since the next point will be off the graph, so we need to go the other way to get another point on the graph. We could slide or trace to find the third point or we could do the opposite and go down 3 and 1 to the left. We can go that because -3/-1 is still 3/1.

The picture on the right:

Our linear equation is like staircase going up and to the right since our slope is positive. Each new point has the same rise and run away from the last. We start at the y-intercept in this case, (0, 1), and go up 3 and to the right 1. 

Example 1:

Here we have the final product at least 3 points plotted.

Example 2

Example 1:

Here we have to graph with the following features: slope = 1/2 and y-intercept = -3.

We plot the y-intercept first, which is at the point (0, -3). Next we using the slope 1/2 to find the next point. We go up 1 and then to the right 2 since our slope is positive. We should always plot at least 3 points because it will be easier to see if we made a mistake with 3 points. Let's talk about the pictures.

The picture on the left:

We started at the y-intercept, (0, -3), and moved 1 up and 2 to the right. We continue this way for the next point but cannot for the next point since the next point will be off the graph. We have our 3 points, but its go the other way as well. We could slide or trace to find the fourth point or we could do the opposite and go down 1 and 2 to the left. We can go that because -1/-2 is still 1/2.

The picture on the right:

Our linear equation is like staircase going up and to the right since our slope is positive. Each new point has the same rise and run away from the last. We start at the y-intercept in this case, (0, -3), and go up 1 and to the right 2

Example 2:

Here we have the final product at least 3 points plotted.

Example 3

We plot the y-intercept first, which is at the point (0, -1). Next we using the slope -3/4 to find the next point. We go down 3 and then to the right 4 since our slope is negative. We should always plot at least 3 points because it will be easier to see if we made a mistake with 3 points. Let's talk about the pictures.

The picture on the left:

We started at the y-intercept, (0, -1), and moved 3 down and 4 to the right. We cannot continue this way since the next point will be off the graph, so we need to return to the y-intercept to go the other way to get another point on the graph. We could slide or trace to find the third point or we could do the opposite and go up 3 and 4 to the left. 

Remember the negative can go out in front of the fraction, in the numerator, or in the denominator, so -(3/4), (-3)/4, or 3/(-4). (-3)/4 equates to down 3 and 4 to the right. 3/(-4) equates to up 3 and 4 to the left.

The picture on the right:

Our linear equation is like staircase going down and to the right since our slope is negative. Each new point has the same rise and run away from the last. We start at the y-intercept in this case, (0, -1), and go down 3 and to the right 4

Example 3:

Here we have the final product at least 3 points plotted.

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