Math 1 · Unit 3 · Lesson 4 · 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 |
|---|---|---|
| Slope-intercept form | y = mx + b: the form that shows the slope and the y-intercept. | Find m, find b, write it. |
| Slope (m) | The rate of change: rise over run, how much y changes per step of x. | From a graph, count. From a table, the constant change. From two points, subtract. |
| y-intercept (b) | Where the line crosses the y-axis: the value of y when x is 0. The starting value. | Read it off the graph or the x = 0 row, or put a point into y = mx + b and solve. |
| x-intercept | Where the line crosses the x-axis: the value of x when y is 0. When the story hits zero. | Put y = 0 in and solve for x. Write it as (x, 0). |
| Put the point in | A point on the line makes y = mx + b true, so its x and y can be substituted. | With m known, solve the one-step equation for b. |
| Walk the table back | If a table skips x = 0, step backward using the constant change until you reach it. | Or just put one row into y = mx + b. |