My Math Forum  

Go Back   My Math Forum > High School Math Forum > Algebra

Algebra Pre-Algebra and Basic Algebra Math Forum

Thanks Tree1Thanks
  • 1 Post By skipjack
LinkBack Thread Tools Display Modes
November 8th, 2018, 12:27 AM   #1
Joined: Jul 2018
From: England

Posts: 3
Thanks: 0

Factor Trinomials Of The Form Ax2 + Bx + C Using Trial And Error.

In the OpenStax Elementary Algebra book in the section on factoring using Trial and Error, there is the following paragraph.

"When we factor an expression, we always look for a greatest common factor first. If the expression does not have a greatest common factor, there cannot be one in its factors either. This may help us eliminate some of the possible factor combinations."

Then there is Example 7.25 which asks the question:

Factor completely: 14x^2 − 47x − 7

It then lists possible factors but dismisses some without checking if they are valid e.g. (x + 1)(14x - 7). Besides the ones it dismisses, it says:

"if the trinomial has no common factors, then neither factor can contain a common factor. That means each of these combinations is not an option."

Could someone expand on this explanation as I don't get what they mean?

BrendanC is offline  
November 8th, 2018, 02:40 AM   #2
Global Moderator
Joined: Dec 2006

Posts: 20,753
Thanks: 2136

The second factor in (x + 1)(14x - 7) has 7 as a common factor of its terms, but 7 isn't a common factor of the trinomial's terms.

14x² − 47x − 7 = (7x + 1)(2x - 7)
Thanks from BrendanC
skipjack is online now  

  My Math Forum > High School Math Forum > Algebra

ax2, error, factor, form, trial, trinomials

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
What Do You Think of Trial and Error? EvanJ Geometry 10 August 22nd, 2017 09:28 PM
can someone explain Factoring Trinomials in the Form x^2+bx+c GIjoefan1976 Algebra 2 April 28th, 2016 04:34 PM
Trial and Improvement Equation Skorpi007 Algebra 14 February 9th, 2015 06:38 AM
Factor perfect square trinomials!! Helppp Jazzy bell Pre-Calculus 4 July 16th, 2014 01:18 AM
Trial and Improvement fliss1992 Algebra 6 May 6th, 2014 07:41 PM

Copyright © 2019 My Math Forum. All rights reserved.