
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
November 8th, 2018, 01:27 AM  #1 
Newbie 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? Thanks. 
November 8th, 2018, 03:40 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,098 Thanks: 1905 
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) 

Tags 
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 10:28 PM 
can someone explain Factoring Trinomials in the Form x^2+bx+c  GIjoefan1976  Algebra  2  April 28th, 2016 05:34 PM 
Trial and Improvement Equation  Skorpi007  Algebra  14  February 9th, 2015 07:38 AM 
Factor perfect square trinomials!! Helppp  Jazzy bell  PreCalculus  4  July 16th, 2014 02:18 AM 
Trial and Improvement  fliss1992  Algebra  6  May 6th, 2014 08:41 PM 