# Lesson 9

Scaling the Inputs

### Lesson Narrative

This is the second of two lessons where students focus on understanding of the effect of scale factors on graphs. The warm-up begins by introducing students to the effect on a graph of multiplying the input of a function by a scale factor. The following activities of the lesson offer opportunities for students to identify and contrast the effect of scale factors on the input and output of functions.

Multiple representations and making connections between the different forms is an important feature of the lesson (MP7). Graphs, tables, and equations are used throughout the lesson to see the effect of scale factors in different ways. Throughout the lesson, encourage students to compare the language they use to describe a graphical transformation with how specific points are transformed and with the algebraic transformations of the equations (MP6).

### Learning Goals

Teacher Facing

• Calculate the scale factor $k$ needed to transform the input of a function to fit a situation.
• Describe (orally and in writing) the effect of a scale factor on the input of a function.

### Student Facing

• Let’s use scale factors in different ways.

### Student Facing

• I can describe the effect of a scale factor on the input of a function.
• I understand the differences between scaling the outputs and scaling the inputs of a function.

Building On