document.write( "Question 305085: How do I complete the square?
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Algebra.Com's Answer #218485 by dabanfield(803)![]() ![]() ![]() You can put this solution on YOUR website! x^2 + 6x + 23 = 0\r \n" ); document.write( "\n" ); document.write( "Rewrie the above as:\r \n" ); document.write( "\n" ); document.write( "x^2 + 6x = -23\r \n" ); document.write( "\n" ); document.write( "To complete the square on the loeft side we need to divide the coefficient on the x term by 2, square it and add the result to both sides:\r \n" ); document.write( "\n" ); document.write( "The coefficient on the x term is 6, so we have (6/2)^2 = 3^2 = 9. Adding 9 to both sides we have:\r \n" ); document.write( "\n" ); document.write( "x^2 + 6x + 9 = -23 + 9\r \n" ); document.write( "\n" ); document.write( "x^2 + 6x + 9 = -14\r \n" ); document.write( "\n" ); document.write( "(x+3)*(x+3) = -14 \n" ); document.write( "(x+3)^2 = -14\r \n" ); document.write( "\n" ); document.write( "Taking the square root of both sides:\r \n" ); document.write( "\n" ); document.write( "(x+3)= +sqrt(-14) and \n" ); document.write( "(x+3)= -sqrt(-14)\r \n" ); document.write( "\n" ); document.write( "Note that sqrt(-14) is a complex number, namely i*sqrt(14).\r \n" ); document.write( "\n" ); document.write( "We have then:\r \n" ); document.write( "\n" ); document.write( "x+3 = i*sqrt(14) \n" ); document.write( "x = -3 + i*sqrt914)\r \n" ); document.write( "\n" ); document.write( "and \r \n" ); document.write( "\n" ); document.write( "x+3 = -i*sqrt(14) \n" ); document.write( "x = -3 - i*sqrt(14)\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |