Slope-intercept form: write an equation from a word problem
Learn with an example
Irma uses 4 centimeters of tape for every present she wraps. Write an equation that shows the relationship between the number of presents x and the tape used y.
Write your answer as an equation with y first, followed by an equals sign.
Make a chart.
| Number of presents (x) | Calculation of tape used (y) | Tape used (y) |
| 1 | 4(1) | 4 |
| 2 | 4(2) | 8 |
| 3 | 4(3) | 12 |
| x | 4(x) | 4x |
Find the pattern: y is 4 times x.
Write this relationship as an equation.
| y is 4 times x |
| ↓ |
| y = 4x |
Kurt jars 4 liters of jam every day. Write an equation that shows the relationship between the days x and the jam made y.
Write your answer as an equation with y first, followed by an equals sign.
Make a chart.
| Days (x) | Calculation of jam made (y) | Jam made (y) |
| 1 | 4(1) | 4 |
| 2 | 4(2) | 8 |
| 3 | 4(3) | 12 |
| x | 4(x) | 4x |
Find the pattern: y is 4 times x.
Write this relationship as an equation.
| y is 4 times x |
| ↓ |
| y = 4x |
Hunter takes 6 quizzes each week. Write an equation that shows the relationship between the number of weeks x and the total number of quizzes y.
Write your answer as an equation with y first, followed by an equals sign.
Make a chart.
| Number of weeks (x) | Calculation of total number of quizzes (y) | Total number of quizzes (y) |
| 1 | 6(1) | 6 |
| 2 | 6(2) | 12 |
| 3 | 6(3) | 18 |
| x | 6(x) | 6x |
Find the pattern: y is 6 times x.
Write this relationship as an equation.
| y is 6 times x |
| ↓ |
| y = 6x |
Let’s Practice!
