PEAZIT Aha card
Go straight to resources ↓Linear functions: constant change and starting value
b is the value at x = 0. a tells how much y changes when x increases by 1. Constant change produces a straight line.
| Expression | Meaning |
|---|---|
| x = 0 → y = 1 | The y-intercept is (0, 1). |
| x = 1 → y = 3 | One step right means two steps up. |
| x = 2 → y = 5 | The change in y is again +2. |
One worked example
- x = 0 → y = 1The y-intercept is (0, 1).
- x = 1 → y = 3One step right means two steps up.
- x = 2 → y = 5The change in y is again +2.
Watch out: The graph passes through the origin only if b = 0. A decreasing line is not automatically inverse proportion.
Goal, prerequisites and card origin
What you will learn: Read slope and y-intercept from y = ax + b.
What you need first: Substitution and point coordinates.
An original PEAZIT working card. Independent expert review and effectiveness testing have not yet taken place. · v1
Show connections
b is the value at x = 0. a tells how much y changes when x increases by 1. Constant change produces a straight line.