Algebra.Com's Answer #841319 by ikleyn(53937)![\"\"](\"/images/stars/stars-13.gif\")  
You can put this solution on YOUR website!
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document.write( "(3 + sqrt(5))*3*(5 + 3*sqrt(5))^3 = ___ + ___* sqrt(5)
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document.write( " What is written in the post by @MathLover1, is FATALLY INCORRECT \r
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document.write( " starting from the third line of her post to the last line, including.\r
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document.write( " I came to bring a correct solution.\r
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document.write( "To make writing easier, replace  by x in the left side of the original expression.\r\n" );
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document.write( "After replacing, you will get this polynomial (3+x)*3*(5+3x))^3.\r\n" );
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document.write( "It is\r\n" );
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document.write( " (3 + x)*3*(5 + 3x))^3 = 81x^4 + 648x^3 + 1890x^2 + 2400x + 1125. (*)\r\n" );
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document.write( "You can do multiplications manually - it is a mechanical procedure.\r\n" );
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document.write( "I myself, caring about my mind, did it using an online calculator\r\n" );
document.write( "https://www.emathhelp.net/en/calculators/algebra-1/multiplying-polynomials-calculator/\r\n" );
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document.write( "Now, to get first integer number of the right side, I consider the terms of this polynomial (*)\r\n" );
document.write( "with even degrees\r\n" );
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document.write( " even(x) = 81x^4 + 1890x^2 + 1125\r\n" );
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document.write( "and substitute there  = 5. \r\n" );
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document.write( "I get then \"first integer number in the answer\" = 81*5^2 + 1890*5 + 1125 = which is easy to compute = 12600.\r\n" );
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document.write( "Next, to get second integer number of the right side, I consider the terms of this polynomial (*)\r\n" );
document.write( "with odd degrees\r\n" );
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document.write( " odd(x) = 648x^3 + 2400x\r\n" );
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document.write( "and substitute there  = 5. \r\n" );
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document.write( "I get then \"second integer number in the answer\" = 648*5 + 2400 = which is easy to compute = 5640.\r\n" );
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document.write( "Therefore, the final ANSWER is  (**)\r\n" );
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document.write( "Finally, to check the answer, I calculated (**) and compared with the left side of the original expression.\r\n" );
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document.write( "I got the same number, which confirms correctness of my solution.\r\n" );
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document.write( "Solved.\r
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document.write( "For safety of your mind, simply ignore the post by @MathLover1,
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document.write( "since it is WRONG.\r
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document.write( "What is shown in my post is HOW TO organize your work and HOW TO do it in other similar cases.\r
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document.write( "Multiplying polynomials of high degree by hand is a torture, which will add
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document.write( "nothing to your mind and/or to your skills, and here is the way how to avoid it.\r
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document.write( "Now, in the XXI century, people/students do it differently than they did it in the past, in the XX century and before.\r
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