document.write( "Question 41196: A picture frame is 20 inches by 12 inches. There are 84inches^2 of the picture showing. Find the width of the frame.
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Algebra.Com's Answer #26602 by fractalier(6550)![]() ![]() You can put this solution on YOUR website! Let the width of the frame be x. Let the dimensions of just the picture be L and W. Thus we know \n" ); document.write( "A = LW = 84 \n" ); document.write( "We also know that \n" ); document.write( "(L + 2x)(W + 2x) = 240 \n" ); document.write( "We also know that \n" ); document.write( "L + 2x = 20 \n" ); document.write( "W + 2x = 12 \n" ); document.write( "Let us solve these for L and W and plug in to the first equation, so we get \n" ); document.write( "L = 20 - 2x \n" ); document.write( "W = 12 - 2x \n" ); document.write( "and then \n" ); document.write( "(20 - 2x)(12 - 2x) = 84 \n" ); document.write( "240 - 64x + 4x^2 = 84 \n" ); document.write( "4x^2 - 64x + 156 = 0 \n" ); document.write( "x^2 - 16x + 39 = 0 \n" ); document.write( "(x - 13)(x - 3) = 0 \n" ); document.write( "x = 13 or x = 3 \n" ); document.write( "but x cannot be 13, so \n" ); document.write( "x = 3 \n" ); document.write( " |