Hi there!
To find the slope of a line when we have 2 points, we use this formula:
m=![\frac{y2-y1}{x2-x1}](https://tex.z-dn.net/?f=%5Cfrac%7By2-y1%7D%7Bx2-x1%7D)
where m is the slope.
![\frac{7-7}{7-3}](https://tex.z-dn.net/?f=%5Cfrac%7B7-7%7D%7B7-3%7D)
Notice that if we subtract the y-coordinates, we get 0. We know that 0 divided by any number is 0.
So the slope of this line is 0.
So if the y-coordinates are the same, then the slope is 0.
Now, let's find the slope of the next line.
![\frac{-5-3}{-4-(-4)} \\\frac{-8}{-4+4} \\\frac{8}{0}](https://tex.z-dn.net/?f=%5Cfrac%7B-5-3%7D%7B-4-%28-4%29%7D%20%5C%5C%5Cfrac%7B-8%7D%7B-4%2B4%7D%20%5C%5C%5Cfrac%7B8%7D%7B0%7D)
Do you see what I see?
We cannot divide by 0 because division by 0 is undefined. So the slope of this line is undefined.
Remember:
- If the y-coordinates are the same, then the slope is 0.
- If the x-coordinates are the same, then the slope is undefined.
Hope this helps you!
~Just an emotional teen who listens to her favorite song "Try Everything"
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