document.write( "Question 1210612: Fill in the blanks to make an equation that is linear in disguise, and has a solution.
\n" ); document.write( "sqrt(2x - 3) + __x + ___ = ___x - ___ + ____
\n" ); document.write( "8 9 10 11 12 13 14 15 16 17 18 19 20
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Algebra.Com's Answer #854412 by KMST(5362)\"\" \"About 
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The way I interpret the question, only the numbers given below the equation can be used to fill the blanks.
\n" ); document.write( "I am going to refer to the values to be filled as the constants A, B, C, D and E.
\n" ); document.write( "I will write the equation as
\n" ); document.write( "\"sqrt%282x+-+3%29+%2B+Ax+%2B+B+=+Cx+-+D+%2B+E\" .
\n" ); document.write( "It is not specified, but I am going to assume that each number can only be used once.
\n" ); document.write( "A linear equation is one where the variable appears multiplied by some coefficient(s), but never with an exponent, or in a square root.
\n" ); document.write( "The square root shown appears to make that equation not linear, so
\n" ); document.write( "I am also going to assume, that the equation to be made is to be \"linear in disguise\" because
\n" ); document.write( "\"sqrt%282x-3%29=0\" for the value of \"x\" that satisfies \"Ax+%2B+B+=+Cx+-+D+%2B+E\" .
\n" ); document.write( "\"sqrt%282x-3%29=0\" <--> \"2x-3=0\" <--> \"x=3%2F2\"
\n" ); document.write( "For \"x=3%2F2\" to be a solution of \"Ax+%2B+B+=+Cx+-+D+%2B+E\" , the values of the constants must be such that
\n" ); document.write( "\"%283%2F2%29A%2BB+=%283%2F2%29C-D%2BE\"<-->\"3A%2B2B=3C-2D%2B2E\"<-->\"3A-3C=2E-2D-2B\"<-->\"3%28A-C%29=2%28E-D-B%29\" .
\n" ); document.write( "The values for A, B, C, D, and E must be all different, be in the list of numbers given, and the numbers given are such that \"0%3Cabs%28A-C%29%3C=20-8=12\" .
\n" ); document.write( "The equation \"3%28A-C%29=2%28E-D-B%29\"<--> \"A-C=2%28E-D-B%29%2F3\" tells us that
\n" ); document.write( "\"A-C\" must be a multiple of 2, and
\n" ); document.write( "\"E-D-B\" must be a multiple of 3.
\n" ); document.write( "From there on, we can guess and check to find suitable answers. There is a very large number of them.
\n" ); document.write( "For example, \"system%28E=20%2CD=8%2CB=9%29\" or \"system%28E=20%2CD=9%2CB=8%29\" give us
\n" ); document.write( "\"E-D-B=20-8-9=3\" and are part of some of the many possible answers.
\n" ); document.write( "Those choices make \"A-C=2%2A3%2F3=2\" ,
\n" ); document.write( "and leaves us the numbers 10, 11, 12, 13, 14, 15, 16, 17, 18, and 19 available to use as A and C.
\n" ); document.write( "Then, \"system%28A=12%2CC=10%29\" , \"system%28A=13%2CC=11%29\" , \"system%28A=14%2CC=12%29\" , \"system%28A=15%2CC=13%29\" , \"system%28A=16%2CC=14%29\" , \"system%28A=17%2CC=15%29\" , \"system%28A=18%2CC=16%29\", \"system%28A=19%2CC=17%29\" could be used to complete an answer.
\n" ); document.write( "There are many other sets of values that are valid answers.
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\n" ); document.write( "Let's verify if \"system%28A=12%2CB=8%2CC=10%2CD=9%2CE=20%29\" make \"sqrt%282x-3%29%2B12x%2B8=+10x-9%2B20\" an equation \"linear in disguise\" that has \"x=3%2F2\" as a solution.
\n" ); document.write( "Substituting \"x=3%2F2\" into \"sqrt%282x-3%29%2B12x%2B8=+10x-9%2B20\" , I get
\n" ); document.write( "\"sqrt%282%283%2F2%29-3%29%2B12%283%2F2%29%2B8=10%283%2F2%29-9%2B20\"
\n" ); document.write( "\"sqrt%283-3%29%2B18%2B8=15-9%2B20\"
\n" ); document.write( "\"sqrt%280%29%2B26=6%2B20\"
\n" ); document.write( "\"0%2B26=26\"
\n" ); document.write( "\"26=26\"
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\n" ); document.write( "For a more systematic approach, we could start with the possible values of \"A-C\" .
\n" ); document.write( "Knowing that \"0%3Cabs%28A-C%29%3C=20-8=12\" , and that \"A-C\" is not zero,
\n" ); document.write( "the possible vales for \"A-C\" are -12, -10, -8, -6, -4, -2, 2, 4, 6, 8, 10, and 12.
\n" ); document.write( "That makes the possible values for \"E-B-D=3%28A-C%29%2F2\" -18,-15,-12, -9, -6 -3, 3, 6, 9, 12, 15, and 18.
\n" ); document.write( "To get a longer list of possible solutions, we could start by using multiples of 3 for E, B, and D to make \"E-B-D\" a multiple of 3.
\n" ); document.write( "Thinking about modular arithmetic, for those familiar with it, we could make a very long list of options for E, B, and D that make \"E-B-D\" a multiple of 3
\n" ); document.write( "Then, we could weed out from those lists those with \"E-B-D=0\" and those with \"abs%28E-B-D%29%3E18\", then we could find possible values of A and C, eliminating the ones where A or C was already used as E, B, or D.
\n" ); document.write( "We are still left with hundreds of different valid answers.
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