document.write( "Question 1210429: 1) Solve 2(√4x+5) - (√3x+1) = 6, where x is an integer.\r
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document.write( "2) Given that sinx = -3/5, where 180° ≤ x ≤ 270° and cos y = - 15/17 , where 90° ≤ y ≤ 180°. find the value of tan(x-y).
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Algebra.Com's Answer #852519 by n2(19) ![]() You can put this solution on YOUR website! . \n" ); document.write( "1) Solve 2(√4x+5) - (√3x+1) = 6, where x is an integer. \n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Tutor @greenestamps made a great step forward, guessing or finding mentally \n" ); document.write( "one integer solution x = 5.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "But when a solution to a Math problem, or a math equation is found by the \" trial and error \" \n" ); document.write( "guessing method, always a question arises - whether this solution is unique or whether other solutions exist.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "There is one brilliant reasoning, which may help in some cases, \n" ); document.write( "and it will help to answer for this given equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Notice that in the left side of the equation the term \n" ); document.write( "the other term, \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "AFORTIORI, the term \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "It means that the left side of the given equation is a monotonic function of x \n" ); document.write( "(monotonically increases for positive values of x).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Hence, this given equation, having a constant value in its right side, has a UNIQUE solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "In other words - if it has one solution, then this solution is unique.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Reasoning this way, we transform our \" trial and error \" guessing method into MATHEMATICALLY STRICT \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So, x = 5 is the unique real and integer solution to this given equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \r\n" ); document.write( " Z Z Z !\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( " Be careful ! That is true that in the positive 'x'-domain the left side monotonically increases.\r\n" ); document.write( "\r\n" ); document.write( " But what about negative 'x' ? - In this problem, the domain of negative 'x' is small and does not \r\n" ); document.write( " make influence to the final conclusion !\r\n" ); document.write( "\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |