6.EE.C.9: Two related quantities

Also written as 6.EE.9

Use variables to represent two quantities in a real-world problem that change in relationship to one another; write an equation to express one quantity, thought of as the dependent variable, in terms of the other quantity, thought of as the independent variable. Analyze the relationship between the dependent and independent variables using graphs and tables, and relate these to the equation.

In plain words: Students write an equation like d = 65t for two quantities that change together, name the dependent and independent variables, and connect the equation to a table and a graph.

Quick picks

Common mistake
Swapping the chosen variables: when hours worked is the independent variable and pay is the dependent variable, putting pay on the horizontal axis reverses their roles.
Builds on
5.OA.B.3Two numerical patterns6.EE.B.6Variables in word problems
Leads to
7.RP.A.2Proportional relationships8.EE.B.5Unit rate as slope
Example Problems
Graph:
Graph:
Graph:
Khan Academy Resources
Dependent and independent variables reviewAnalyze relationships between variablesMatch equations to coordinates on a graphRelationships between quantities in equationsTables from equations with 2 variablesIndependent versus dependent variablesDependent & independent variables: graphingDependent & independent variablesDependent & independent variablesAnalyzing relationships between variablesWriting equations for relationships between quantitiesDependent & independent variables: equation
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