
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
November 2nd, 2011, 06:27 AM  #1 
Newbie Joined: Nov 2011 Posts: 21 Thanks: 0  stuck simplifying a quadratic, please help
I'm practicing for the SAT, and found this questions in a Princeton Review practice test: 2x^2 + x  28 x^2  3x  28 = ? here are the options: A. 2x7 x7 B. 2x+1 x3 C. x2 x+14 D. 2 3 E. The expression cannot be simplified.  I thought the answer is E, but according to the answer key it isn't. I know that I can simplify the denominator from: x^23x28 to: (x7)(x+4) but I have no idea about the numerator. Thanks for any help. 
November 2nd, 2011, 06:36 AM  #2 
Global Moderator Joined: Nov 2009 From: Northwest Arkansas Posts: 2,766 Thanks: 4  Re: stuck simplifying a quadratic, please help
a = 2 b = 1 c = 28 ac = 56 = 8*(7) So we can rewrite 2x^2 + 8x 7x 28 and factor by grouping. 
November 2nd, 2011, 06:58 AM  #3  
Math Team Joined: Sep 2007 Posts: 2,409 Thanks: 5  Re: stuck simplifying a quadratic, please help Quote:
1) To have we must have a=2 and b= 4 to get and . Does that work? . No, that doesn't work. 2) To have we must have a= 2 and b= 7. Does that work? . Yes!! Quote:
 
November 2nd, 2011, 12:52 PM  #4 
Newbie Joined: Nov 2011 Posts: 21 Thanks: 0  Re: stuck simplifying a quadratic, please help
I'm sorry, I've lost you. I'm probably lacking some knowledge that you assume in your explanations. To establish a starting point I can work with, here's what I do know: I know that an equation of this form [ x^2+bx+c ] can be simplified, if I can think of two numbers that sum up to [b] and multiply to [c]. If those numbers are [p] and [q], I can simplify: (x+p)(x+q). What throws me off if the coefficient of the xsquared in the equation above: [2x^2 +...] instead of [x^2 +...]. I don't know how to deal with that. If you could walk me through this again, from here, I'd appreciate it. 

Tags 
quadratic, simplifying, stuck 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Really stuck  FallenKnightRus  Calculus  2  March 17th, 2014 07:34 PM 
stuck  mathkid  Algebra  3  November 10th, 2012 09:24 PM 
please help!!! I am so stuck!  smilez750  Algebra  2  November 14th, 2011 03:48 AM 
So now you are stuck with me  MathyMattyCalls  New Users  3  April 22nd, 2010 11:22 AM 
stuck  mathkid  Calculus  3  January 1st, 1970 12:00 AM 