I need to know how to find the slope of a line using just a graph?

Question

i have no equation to use, this is algebra 2. one of the points on the graph is (0, -1) this was not included but i gathered it from the graph. Can someone please help me?

Update : thank both of yall. the second one helped, even though i used the bottom ...show more

Answer 1

Slope is a concept in the algebra field of mathematics. Every high school student is required to pass algebra in order to graduate, and the only way to do that is to learn how to find the slope of a graph. Slope is very simply the increase or decrease of a line between two points. Many times this information is presented in a way that makes in seem very difficult, however, slope can be fairly easy to find

Instructions.1.1
Familiarize yourself with the way a graph is set up. Graphs in algebra have a series of vertical numbers evenly spaced on what is known as the "y-axis." There are also a series of horizontal numbers evenly spaced on a line known as the "x-axis." All numbers to the right of the number zero on the x-axis are positive, and all numbers on the x-axis that are left of the zero are negative. Similarly, all number higher than the zero on the y-axis are positive, while all numbers lower than the zero on the y-axis are negative.

2.2
Find the "origin." The origin is the name that is given to represent the intersection of the x and y axises. If you were asked to give the "plot points" or the location of the origin on the graph, it would be represented as (0,0). This is because it is located at "0" on the x-axis, which is always the first number in the parenthesis, and it is also "0" on the y-axis, which is always listed second in the plot point.

3.3
Find the plot points for the two points on the graph in which you are trying to the slope. You can choose any two points on the line, however, it is always easiest to pick the one point where the line crosses the x-axis, and the one point where the line crosses the y-axis. For this example, use the graph pictured at the top of this article. You will see that the line goes through the number -2 on the x-axis. This plot point is represented as (-2,0). We also see that the line goes through the y-axis at its +2, so the y-axis plot point is (0,2).

4.4
Calculate the slope of the line by finding its "rise over run." To find this, simply start at the left most point, then find the rise by seeing how many positive or negative numbers you have to go up to get on the same line that the second point is located. For the example that is pictured, you would have to go up two positive numbers to be on the same line as the y-axises plot point. Then find the run by seeing how many positive or negative numbers you have to move over to hit the second point exactly. For this example, you would have to move over two positive numbers to hit the point. This means that the slope of this line is +2/+2, which can also simply be represented as 1.

5.5
Calculate the slope of a line on a graph by using a formula. The formula to find slope is; (y2-y1)/(x2-x1). This simply means that you first get the two plot points the same way you did in step 3, then you just plug the numbers into the formula. The first plot point will be for the numbers (x1,y1) and the second plot points will be the numbers (x2,y2). For the example that you have been using, the formula for this slope would look like; (2-0)/0- -2), which equals 2/2, the same slope you found in Step 4.



Read more: How to Find the Slope on a Graph | eHow.com http://www.ehow.com/how_5060900_slope-gr...


Read more: How to Find the Slope on a Graph | eHow.com http://www.ehow.com/how_5060900_slope-gr...

Answer 2

An easier way is just look at the graph and count.

http://library.thinkquest.org/18713/medi...
I'm gonna use this graph as an example. Make sure to look so you know what I'm talking about.

So choose any point on the line. Its always easy to choose on where the line crosses the x or y axis, but it doesn't matter.

I'm gonna choose the point (-1,0), now all you do is count how many units you need to go up (rise) and over (run) to get back to another point on the line. So you count up 2 units, and over 1 unit. So the slope is rise over run, So the slope of this line is 2/1.

This is much easier than having to plug in points to the slope formula. (x1, y1), (x2, y2).
y2-y1
_____
x2-x1

But it can be performed both ways.

Lol. Happy graphing. :)

Source(s):

High School Student, In Analysis.

Answer 3

http://www.youtube.com/watch?v=IyfpM-rua...

this helped me a lot!!

slope = y2-y1 over x2-x1

so if your points are (0,1) and (7,10) you would take 10-1 over 7-0 which is 9 over 7, so your slope of the points (0,1) and (7,10) is (9,1) which is the same as moving left 9 and up one every time you find a new point

Source(s):

www.youtube.com