8.F.B.4: Linear function models

Also written as 8.F.4

Construct a function to model a linear relationship between two quantities. Determine the rate of change and initial value of the function from a description of a relationship or from two (x, y) values, including reading these from a table or from a graph. Interpret the rate of change and initial value of a linear function in terms of the situation it models, and in terms of its graph or a table of values.

In plain words: Students write a linear function for a situation, find its rate of change and initial value from a description, two points, a table, or a graph, and explain what each means.

Quick picks

GoblinsTeach it with
When do you turn back?8th grade · Negative rate of change · 2 min
Common mistake
Taking the first y-value in a table as the initial value when the table does not start at x = 0.
Builds on
8.EE.B.6Slope from similar triangles8.F.A.3Linear vs. nonlinear functions
Leads to
HSF.BF.A.1Writing functionsHSF.LE.A.2Linear and exponential functions
Example Problems
What is the slope of the following line?
What is the slope of the following line?
What is the slope of the following line?
Khan Academy Resources
Intro to slopeSlope formulaSlope reviewSlope-intercept form reviewWriting linear functions word problemsSlope from two pointsSlope-intercept from two pointsSlope in a tableSlope from graphRelating linear contexts to graph featuresSlope-intercept equation from graphLinear equations in any formSlope from equationWorked example: slope from graphConverting to slope-intercept formSlope of a line: negative slopeWorked example: slope from two pointsSlope of a horizontal lineSlope & direction of a linePositive & negative slopeSlope from equationGraphing a line given point and slopeCalculating slope from tablesSlope and y-intercept from equationWorked examples: slope-intercept introHorizontal & vertical linesIntro to slope
Goblins

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