Using the Point-Slope Form of a Line Another way to express the equation of a straight line Point-slope refers to a method for graphing a linear equation on an x-y axis. While you could plot several points by just plugging in values of x, the point-slope form makes the whole process simpler. Point-slope form is also used to take a graph and find the equation of that particular line. The point slope form gets its name because it uses a single point on the graph and the slope of the line.
In the previous lesson, Calculating Slopeyou learned how to calculate the slope of a line. In this lesson, you are going to graph a line, given the slope. We are still going to use the definition of slope, which is: You must have at least two points to draw a line.
Let's take a look at the directions and an example. In the next lesson, Graphing with Slope Intercept Form, you will learn the exact point that needs to be plotted first. For right now, we are only focusing on slope.
Look at the numerator of the slope. Count the rise from the point that you plotted. If the slope is positive, count up and if the slope is negative, count down. Look at the denominator of the slope. Count the run to the right.
Repeat the above steps from your second point to plot a third point if you wish. Draw a straight line through your points. In this example, we are only focusing on how to count the slope and plot the next point. We are not graphing an actual equation.
If you need help with graphing an actual equation and need to know which point to plot first, visit our lesson on Slope Intercept Form. Graphing a Positive Slope Start with the point 0, Plot the 1st point. Since the rise is positive 2, I counted up 2.
Since the run is positive 3, I counted to the right 3. Plot your second point. This point is 3,0 5. Repeat the process to plot a third point. In the next example, we will graph a line with a negative slope. One other thing to think about as we complete Example What do we do when the slope doesn't have a denominator?
Let's say the slope is Can we write -3 as a fraction? Negative Slopes are Tricky!To summarize how to write a linear equation using the slope-interception form you. Identify the slope, m. This can be done by calculating the slope between two known points of the line using the slope formula.
Writing linear equations using the slope-intercept form; Mathplanet is licensed by. ©d 82P0k1 f2 T 1K lu9t qap 2S ho KfZtgw HaTrte I BL gLiCQ.e R xA NlOlh JrKi0gMh6t8sq YrCenshe Rr8vqeed Y JMGapdQeX TwGiRt VhW 8I 2n fDiPn 8iDtEep QAVlVgue3bjr vaV Y The equation of a line is typically written as y=mx+b where m is the slope and b is the y-intercept..
If you know the slope (m) any y-intercept (b) of a line, this page will show you how to find the equation of the line. You may already be familiar with the "y=mx+b" form (called the slope-intercept form of the equation of a line).
It is the same equation, in a different form! The "b" value (called the y-intercept) is where the line crosses the y-axis.
When you are given a point and a slope and asked to write the equation of the line that passes through the point with the given slope, you have to use what is called the point-slope form of a line.
When using this form you will substitute numerical values for x 1, y 1 and m. Straight-line equations, or "linear" equations, graph as straight lines, and have simple variable expressions with no exponents on them. If you see an equation with only x and y – as opposed to, say x 2 or sqrt(y) – then you're dealing with a straight-line equation.