Two points on a line cue the slope formula: change in divided by change in . Subtract coordinates in the same point order on top and bottom, then enter the fraction in Desmos. Reversing only one subtraction changes the sign, making a line that rises as increases appear to fall.
Hints
- Hint 1
The slope tells you how much changes for each unit increase in . From the first point to the second, which -values should you subtract? Which -values belong underneath?
- Hint 2
Use second point minus first for both changes. That keeps each -value paired with its -value. Put the change on top of the fraction, then let Desmos evaluate it.
Step-by-step
Find the change in per change in
Step 1Write the slope as a fraction
A slope is the change in divided by the matching change in . Moving from to , the change is and the change is . Keep the same point order in both subtractions: . Reversing only one subtraction would give the wrong sign.
- Step 2
Evaluate the fraction
Type into Desmos. It prints , so rises by for each unit increase in . The line’s slope is . Grid in 2.