8th Grade · Functions
Rate of Change
8.F.A.2
Definition
How much the output quantity changes per unit change in the input, found as change in y divided by change in x. For a line it equals the slope.
Examples
- A plant grows 3 cm per week — rate of change = 3 cm/week.
- Rate of change = change in y ÷ change in x.
Key rule
For a linear function, rate of change is constant and equals the slope.
Memory hook
How much y changes for each step in x.