document.write( "Question 1189159: Solve the roots of the equation by completing the square. Leave all answers in exact values with the most simplified form:\r
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document.write( "3x^2 + 2x + 7/3 = 0 \n" );
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Algebra.Com's Answer #820418 by Theo(13342)![]() ![]() You can put this solution on YOUR website! i solved by completing the square as shown in the following worksheet.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 1 was just copying down the equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 2 was dividing both sides of the equation by 3 to make the coefficient of the x^2 term equal to 1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 3 was subtracting 7/9 from both sides of the equation to get the constant term on the right side of the equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 4 is where the magic occurs. \n" ); document.write( "the equation at the start of this step is x^2 + 2/3 * x = -7/9. \n" ); document.write( "you take the square root of the x^2 term and 1/2 the coefficient of the 2/3 * x term to get: \n" ); document.write( "(x + 2/6)^2 - (2/6)^2 = -7/9 \n" ); document.write( "the reason you are subtracting (2/6)^2 is because: \n" ); document.write( "(x + 2/6)^2 is equal to x^2 + (4/6)x + (2/6)^2 \n" ); document.write( "since you only want x^2 + (4/6)x, you need to subtract (2/6)^2 to get: \n" ); document.write( "(x + 2/6)^2 = x^2 + (4/6)x + (2/6)^2 - (2/6)^2 which cancels out the (2/6)^2 so you are left with: \n" ); document.write( "(x^2 + 2/6)^2 - (2/6)^2 = x^2 + (4/6)x. \n" ); document.write( "you then add (2/6)^2 to both sides of the equation to get: \n" ); document.write( "(x + 2/6)^2 = -7/9 + (2/6)^2 \n" ); document.write( "that's the equation you see in step 4, which was the result of what i showed you above.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the instructions you will most likely see would be: \n" ); document.write( "x^2 + (2/6)x = -7/9 becomes: \n" ); document.write( "(x + 2/3)^2 = -7/9 + (2/6)^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 5 simplifies the equation as shown below: \n" ); document.write( "(x + 2/6)^2 = -7/9 + (2/6)^2 becomes: \n" ); document.write( "(x + 2/6)^2 = -7/9 + 4/36 which becomes: \n" ); document.write( "(x + 2/6)^2 = -7/9 + 1/9 which becomes: \n" ); document.write( "(x + 2/6)^2 = -6/9 which becomes: \n" ); document.write( "(x + 2/6)^2 = -2/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 6 take the square root of both sides of the equation to get: \n" ); document.write( "(x + 2/6)^2 = -2/3 becomes: \n" ); document.write( "x + 2/6 = plus or minus sqrt(-2/3)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 7 subtracts 2/6 from both sides of the equation to get: \n" ); document.write( "x = -2/6 plus or minus sqrt(-2/3)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since sqrt(-2/3) is equal to sqrt(2/3 * -1) which is equal to sqrt(2/3) * sqrt(-1), and since sqrt(-1) is equal to i, your answer becomes;\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = -2/6 plus or minus sqrt(2/3) * i.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that's your answer before converting everything to decimal. \n" ); document.write( "if they want the answer in that form, you're done.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if they neet it to be in decimal format, then:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "step 7 converts x = -2/6 plus or minus sqrt(-2/3) to: \n" ); document.write( "x = -.3333 plus or minus .8165 * i, when rounded to 4 decimal places.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i checked with an online quadratic equation solver at .\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "it gave me the same answer, confirming that i did it right, as shown below:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "their answer not rounded to 4 decimal places. \n" ); document.write( "it is a more complete answer, probably rounded to 6 decimal places.. \n" ); document.write( "you may round it as required.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "here's a reference on how to solve a quadratic equation by completing the square.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "https://www.purplemath.com/modules/sqrquad.htm\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "let me know if you have any questions.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "theo\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |