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LEVEL 1 ยท SUPPORT

Relationships Between Variables

Standard: 6.EE.C.9 (Independent & Dependent Variables, Tables, Graphs, Equations)

Directions: Read the vocabulary box and worked examples. Then answer each problem. Use tables and equations to organize your thinking. Show your work.

Vocabulary Helper

๐ŸŽฎ Independent Variable (x)
The variable YOU choose or change. Usually the input.
๐Ÿ“ˆ Dependent Variable (y)
The variable that changes because of the other. Usually the output.
๐Ÿ“‹ Input-Output Table
A table showing x-values and the matching y-values.
๐Ÿ“Š Coordinate Graph
Points (x, y) plotted to show a relationship.
๐Ÿ“ Equation (Rule)
A formula connecting x and y, like y = 2x + 1.
๐Ÿ” Rate / Pattern
How much y changes each time x goes up by 1.

Worked Examples

EXAMPLE A โ€” Independent vs. Dependent

A baker earns $8 per hour.

  1. You choose the hours โ†’ hours (h) is independent.
  2. Pay depends on hours โ†’ total pay (p) is dependent.
  3. Equation: p = 8h.
EXAMPLE B โ€” Make a Table from y = 2x + 1

Plug each x-value into the rule:

x y = 2x + 1 y (x, y)
0 2(0)+1 1 (0, 1)
1 2(1)+1 3 (1, 3)
2 2(2)+1 5 (2, 5)

Sentence Frames

The independent variable is because I choose it. The dependent variable is because it changes because of the other.
For the rule y = 4x, when x = 3, I replace x with 3 to get y = .
Each time x goes up by 1, y goes up by in the equation y = 5x.

Guided Practice

1. A taxi charges $3 per mile. Which is the independent variable: miles or total cost?

Hint: You choose how far to ride.

2. Write an equation: you earn $6 for each lawn you mow.

Hint: y = 6 ร— (number of lawns).

3. For y = 4x, find y when x = 3.

Hint: y = 4(3).

4. Complete the table for y = x + 5. x: 0, 1, 2, 3 โ†’ y: ?, ?, ?, ?

Hint: Add 5 to each x-value.

5. What is the ordered pair when x = 2 and y = 10?

Hint: Ordered pairs are written (x, y).

6. For y = 3x, find y when x = 5.

Hint: y = 3(5).

7. A movie streams 2 episodes per hour. Write a rule for episodes (y) after x hours.

Hint: y = 2x.

8. In a table, when x = 0 โ†’ y = 4, x = 1 โ†’ y = 5, x = 2 โ†’ y = 6. What is the rule?

Hint: y is always x plus the same number.

9. For the rule y = 2x, complete: x = 4 โ†’ y = ?

Hint: y = 2(4).

10. A plant grows 3 cm each week. Which variable depends on the other: weeks or height?

Hint: Height changes because of the weeks.

Answer Key

  1. Miles (independent); total cost is dependent
  2. y = 6x (x = lawns, y = money)
  3. y = 12
  4. y: 5, 6, 7, 8
  5. (2, 10)
  6. y = 15
  7. y = 2x
  8. y = x + 4
  9. y = 8
  10. Height depends on weeks (weeks independent, height dependent)