Math 1 · Unit 2 · Lesson 1 · part 5 of 8
Tables: two ways of writing the same thing
Take the rule y = x + 3, which is the same as f(x) = x + 3.
Tables: two ways of writing the same thing
Take the rule y = x + 3, which is the same as f(x) = x + 3. Pick some x values, feed each one in, and write what comes out. Here is the same table written both ways. Every row is a point.
| x | y = x + 3 | point |
|---|---|---|
| −3 | 0 | (−3, 0) |
| −1 | 2 | (−1, 2) |
| 0 | 3 | (0, 3) |
| 2 | 5 | (2, 5) |
| x | f(x) = x + 3 | point |
|---|---|---|
| −3 | f(−3) = 0 | (−3, 0) |
| −1 | f(−1) = 2 | (−1, 2) |
| 0 | f(0) = 3 | (0, 3) |
| 2 | f(2) = 5 | (2, 5) |
Check a table with a spreadsheet.
- Type the x values down column A:
-3in A1,-1in A2,0in A3,2in A4. - In B1 type
=A1+3and press Enter. - Click B1, grab the little square in its corner, and drag it down to B4. The formula copies, and column B fills with the outputs. Column A is your x, column B is your y. Each row is a point.
- Use this trick to check any table in this lesson. Just change the formula in B1 to match the rule.