Algebra Pre-Algebra and Basic Algebra Math Forum

 April 8th, 2014, 05:46 PM #1 Newbie   Joined: Apr 2014 From: california Posts: 2 Thanks: 0 4(x^2+4)=9+12x ^ is a power sign so x^2 is x squared 4(x^2+4)=9+12x 4x^2+16=9+12x 4x^2-12x+7=0 divide all by 4 x^2-3x+7/4=0 i am stuck here the answer sheet says this is the answer 3 +or- √2 2 April 8th, 2014, 06:16 PM #2 Senior Member   Joined: Dec 2013 From: Russia Posts: 327 Thanks: 108 Use the quadratic formula. Thanks from MarkFL and TheReginald April 8th, 2014, 09:32 PM #3 Newbie   Joined: Apr 2014 From: california Posts: 2 Thanks: 0 So using that formula it eventually gets to 12+or- 4√2 8 then if thats correct how do you continue to get? 3+or- √2 2 April 8th, 2014, 09:35 PM #4 Senior Member   Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,211 Thanks: 522 Math Focus: Calculus/ODEs Factor a 4 from the numerator, and then cancel or divide out common factors: $\displaystyle \frac{12\pm4\sqrt{2}}{8}= \frac{\cancel{4}\left(3\pm\sqrt{2} \right)}{\cancel{4}\cdot2}= \frac{3\pm\sqrt{2}}{2}$ Thanks from TheReginald Tags 12x, 4x2 Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

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