The formula for point slope form is: y = mx + b
First, you need to understand what each variable means in this formula.
• y is your y variable (this can mean any vertical number on the graph)
• m is your SLOPE (this is always RISE/RUN)
• rise is your y value. run is your x value.
• x is your x variable (this can mean any horizontal number on the graph)
• b is your Y-INTERCEPT. y-intercept is the number where the line connects on the y axis.
Now that I’ve explained that, let’s solve the problem.
Don’t worry about your x and y variables in the equation. We leave those as they are. What you need to find to put this in point slope form is your y-intercept and slope. Here’s how to find that:
Your slope is rise/run (rise over run). This means you count the numbers up and across. This is shown in the picture in red. Notice you go up 4 units before reaching the same y number. This means your rise is 4.
Now fine the run. Count across now. There are 6 units from the first point to the last point across. Remember the formula. Rise/Run. If your rise is 4 and your run is 6, your slope is 4/6. Now, you have to simplify this fraction. 4 and six can both be divided by 2. Divide both numbers by 2 to get an equivalent fraction of 2/3.
2/3 is your slope.
Now let’s find the y-intercept. Where does your line connect on the y axis? This location is circled in blue. What is the y value there where the line intercepts (interrupts) the y-axis?
The answer is -1, because it’s 1 below the origin (zero) on the graph. The y-axis is always vertical.
Now input this answers into your formula.
• m is your slope
• b is your y intercept
The formula is y = mx + b.
Your exact equation of this graphed line would be:
y = 2/3x - 1
(Fraction 2/3 times x. Write x next to your fraction, where the numbers are stacked on top of each other)
b is a positive value. A positive and a negative make a negative.
Rather than writing y = 2/3x + -1
You can simplify this to simply y = 2/3x - 1.
I hope this helps <3
