document.write( "Question 1199644: Find three consecutive positive even integers such that the
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document.write( "product of the median and largest integer is 6 less than 21 times
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document.write( "the smallest integer.. \n" );
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Algebra.Com's Answer #833599 by math_tutor2020(3816)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Answer: 14, 16, 18\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "=====================================================================\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Explanation:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Consecutive integers follow one after another. \n" ); document.write( "Example: 4, 5, 6 \n" ); document.write( "Each adjacent neighboring item has a gap of 1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Consecutive even integers are the same idea, but all of the values must be even. \n" ); document.write( "Example: 8, 10, 12 \n" ); document.write( "Each adjacent neighboring item has a gap of 2.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let x be a positive even number from the set {2, 4, 6, 8, ...}\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 1st even integer \n" ); document.write( "x+2 = 2nd even integer = median = middle \n" ); document.write( "x+4 = 3rd even integer \n" ); document.write( "The gap from x to x+2 is +2, and the gap from x+2 to x+4 is also +2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(x+2)*(x+4) = \"product of median and the largest integer\" \n" ); document.write( "21x-6 = \"Six less than 21 times the smallest integer\" \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "\"The product of the median and largest integer is 6 less than 21 times the smallest integer\" translates to \n" ); document.write( "(x+2)*(x+4) = 21x-6\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We'll expand things out and get everything to one side \n" ); document.write( "(x+2)*(x+4) = 21x-6 \n" ); document.write( "x^2+6x+8 = 21x-6 \n" ); document.write( "x^2+6x+8-21x+6 = 0 \n" ); document.write( "x^2-15x+14 = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Then you have a few options at this point.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "One method is to factor like so: \n" ); document.write( "x^2-15x+14 = 0 \n" ); document.write( "(x-1)(x-14) = 0 \n" ); document.write( "x-1 = 0 or x-14 = 0 \n" ); document.write( "x = 1 or x = 14\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We ignore x = 1 since x must be even. \n" ); document.write( "Therefore, x = 14 is the only solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-----------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Another method of solving:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We can apply the quadratic formula \n" ); document.write( "x^2-15x+14 = 0 is of the form ax^2+bx+c = 0 \n" ); document.write( "where, \n" ); document.write( "a = 1 \n" ); document.write( "b = -15 \n" ); document.write( "c = 14 \n" ); document.write( "So, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "We arrive at the same two solutions found earlier. \n" ); document.write( "And as mentioned earlier, we ignore x = 1 to go for x = 14.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-----------------------------------------------\r \n" ); document.write( "\n" ); document.write( "A third method:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Graph out y = x^2-15x+14 using a TI calculator, Desmos, or GeoGebra. \n" ); document.write( "There are tons of options out there so feel free to use your favorite graphing calculator.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The parabola crosses the x axis at the locations (1,0) and (14,0) which shows that x = 1 and x = 14 are the two solutions or roots.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The term \"x intercept\" is another way of saying \"root\" or \"zero of a function\". \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-----------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If x = 14, then, \n" ); document.write( "x+2 = 14+2 = 16 \n" ); document.write( "x+4 = 14+4 = 18\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So that's how we arrive at 14, 16, 18 as the final answer.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Check: \n" ); document.write( "median*largest = 16*18 = 288 \n" ); document.write( "21*smallest-6 = 21*14-6 = 288 \n" ); document.write( "This confirms that the equation (x+2)(x+4) = 21x-6 is correct when x = 14, and confirms the final answer. \n" ); document.write( " \n" ); document.write( " |