Key Formulas
Slope: m = (y₂ − y₁) / (x₂ − x₁)
Parabola vertex x: x = −b / 2a
Parabola vertex x: x = −b / 2a
Common Mistakes
- Mixing up rise and run in the slope formula — it's change in y over change in x, not the reverse.
- Connecting graph branches through an asymptote — functions like 1/x have separate, disconnected pieces.
- Choosing too narrow a viewing window and missing key features like roots or turning points.
Frequently Asked Questions
What does a negative slope mean visually?
The line falls from left to right — as x increases, y decreases, the opposite of a positive slope's upward trend.
What does it mean if slope is undefined?
A vertical line has an undefined slope because the change in x is zero, which would require dividing by zero in the slope formula — vertical lines simply have no defined slope value.
