# Activities

• • • ##### Subject Area

• Math: Algebra I: Quadratic Functions

• ##### Author 9-12

60 Minutes

• ##### Software

TI InterActive!™

• ##### Other Materials
This is Activity 6 from the EXPLORATIONS Book:
TI InterActive! Math for High School

## The Standard Form of a Quadratic equation

#### Activity Overview

In this activity, students explore the standard form of a quadratic equation, y = ax 2 + bx + c. They explore how the x-intercepts (zeros), y-intercept, and vertex are related to the graph of the standard form of a quadratic function.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print pages 49 - 53 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to the class.

• Define and graph a quadratic equation
• Determine the values of the x-intercepts
• Observe that these are the points where the graph crosses the x-axis
• Determine the value of the y-intercept
• Observe that this is the point where the graph crosses the y-axis
• Determine the coordinates of the vertex, the point with the lowest value of y
• Find the value of y for x = -4, -1, 0, and 2
• Find the zeros and factors of the expression
• Find the zeros of the factors
• Observe that the zeros of each factor and zeros of the function are the same, and also the zeros of the function and the x-intercept are the same
• Observe that the x-intercepts can be found without graphing, by first finding the factors, and then finding their zeros
• Observe that the value of y when x = 0 and the y-intercept are the same
• #### After the Activity

Students complete the Student Activity sheet.

Review student results:

• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary