Reflection: Connection to Prior Knowledge Factoring Cubic Equations - Section 3: Making Use of Structure


As we begin factoring cubic equations, it's important to build on the students prior knowledge.  From Algebra 1, I find that many of my students are familiar with (and like to use) a "box" or "array" method.

At several points during this class, I'll take some time to explain in detail how this method can be applied to cubic functions.  The most important point is that the array must now change from a 2 x 2 box to to a 2 x 3 box.  This is due to the fact that a cubic must be divisible into one linear and one quadratic factor.  The linear factor may have up to two terms, while the quadratic may have up to three terms.

You can see one example of this method worked out on my whiteboard here and another here.

  Connection to Prior Knowledge: Methods of Factoring
Loading resource...

Factoring Cubic Equations

Unit 3: Cubic Functions
Lesson 4 of 13

Objective: SWBAT factor a sum or difference of two cubes. SWBAT use the distributive law to multiply a binomial by a trinomial.

Big Idea: The factored form is just as useful for solving and graphing cubic polynomials as it was for quadratics!

  Print Lesson
1 teacher likes this lesson
Math, polynomial functions, factoring polynomial expressions, cubic equations, Algebra 2, master teacher project, cubic functions, Algebra 2, function
  45 minutes
cubic polynomial
Similar Lessons
Sketching Graphs of Polynomial Functions
12th Grade Math » Polynomial and Rational Functions
Big Idea: Build upon existing knowledge of second and third degree functions to sketch graphs of other polynomial functions.
Troy, MI
Environment: Suburban
Tim  Marley
Combining Like Terms
Algebra I » Linear Equations
Big Idea: Students will identify the parts of an expression using math terminology. Students will understand the concept of like terms with the use parallel examples.
Washington, DC
Environment: Urban
Noelani Davis
Vertex Form to Standard Form
Algebra I » Quadratics!
Big Idea: Students apply the multiplication models they have recently learned to the task of rewriting quadratic functions from vertex form into standard form.
Boston, MA
Environment: Urban
Amanda Hathaway
Something went wrong. See details for more info
Nothing to upload