Math 1 · Unit 3 · Lesson 5 · part 1 of 6

The Words We Use

The vocabulary for this lesson, in one place.

Words we use

Word	Plain English	What you do
Rate	The slope m in a story: the per-something amount, per hour, per mile, per ticket.	Read it as the number that repeats each step. Negative if the amount goes down.
Starting value (initial value)	The y-intercept b in a story: what you have when x is 0, the flat fee, the amount at the beginning.	Read it as the one-time amount.
Constant rate of change	The same change every step. What makes a situation linear.	Subtract down a table with equal steps. All the same: linear.
Linear	Changes by the same amount each step, so the graph is a line and the rule is y = mx + b.	Write the model as (rate) × x + (start).
Not linear	The rate itself changes: the change grows or shrinks as you go.	Differences down the table are not all the same.
Compare across representations	The same kind of function given as an equation, a graph, a table, or a story.	Get m and b out of each. Bigger b starts higher; bigger m grows faster; set them equal to find when they match.