Reflection: Connection to Prior Knowledge Roots of Polynomial Functions - Day 1 of 2 - Section 1: Launch


When I taught this lesson for the second time I knew I needed to add a warm-up problem to get students thinking about factorization. I put the following problem on the board: If 29 and 107 are prime factors of 46545, then find the other prime factors.

I was surprised that many students simply started from the bottom (2, 3, 5, 7, 11, etc.) and were just using guess and check to test all prime numbers without taking into account the known factors (29 and 107). This was eye opening to me and it was a misconception I wanted to clear up so students wouldn't use guess and check for finding factors of polynomials.

One student set up a factor tree and divided out the prime factors she already knew in order to get the number to be much smaller. It really made sense to students and was helpful once we started working with polynomials and factors that we could figure out easily from a graph.

  Connection to Prior Knowledge: Warm-Up Problem
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Roots of Polynomial Functions - Day 1 of 2

Unit 2: Polynomial and Rational Functions
Lesson 3 of 12

Objective: SWBAT use factoring and division to find roots of polynomial functions.

Big Idea: Factoring and dividing polynomials is analogous to factoring and dividing numbers - use that to your advantage!

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3 teachers like this lesson
Math, polynomial functions, Precalculus and Calculus, factoring polynomial expressions, graphing calculator, zeros of a function, polynomial division, synthetic division
  48 minutes
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