Hello.
To find the slope, use the formula:
m= (y2-y1) / (x2-x1)
Note: The 2s and 1s are NOT exponents or constants. They are simply markers.
So:
m= (5-(-4)) / (2-0)
m= (5+4) / 2
m = 9/2
Note: The order of the coordinates don't matter as long as y2 is aligned with x2 etc.
Example: (okay)
m= ((-4)-5) / (0-2)
m= -9/ -2
m= 9/2 because a negative multiplied or divided by a negative makes a positive.
Now, let's see what's not okay:
(2,5)(0,-4)
m= (5-(-4)) / (0-2)
NOT. OKAY. since the 1s and 2s aren't aligned.
Hope that helped.
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Disclaimer:
Always double check with a reliable source, as mistakes can be made.