document.write( "Question 1079944: Over the last 3 evenings, Latoya received a total of
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document.write( "77 phone calls at the call center. The third evening, she received
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document.write( "5 fewer calls than the first evening. The second evening, she received
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document.write( "2 times as many calls as the third evening. How many phone calls did she receive each evening?
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Algebra.Com's Answer #694172 by Theo(13342) You can put this solution on YOUR website! she received 77 calls total.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "let x = the number of calls she received the first evening \n" ); document.write( "let y = the number of calls she received the second evening. \n" ); document.write( "let z = the number of calls she received the third evening.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + y + z = 77\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the third evening she received 5 fewer calls than the first evening.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "z = x - 5\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the second evening she received 2 times as many call as as the third evening.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 2z\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you have the following 3 equations that need to be solved simultaneously,\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + y + z = 77 \n" ); document.write( "z = x - 5 \n" ); document.write( "y = 2z\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you want to eliminate 2 of the variables in the first equation so you can solve for the third.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "replace z with x - 5 in the first equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + y + x - 5 = 77\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "combine like terms to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2x + y - 5 = 77\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "in the equation of y = 2z, replace z with x - 5 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 2 * (x - 5)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify to get y = 2x - 10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "in the equation of 2x + y - 5 = 77, replace y with 2x - 10 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2x + 2x - 10 - 5 = 77\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "combine like terms to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "4x - 15 = 77\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "add 15 to both sides of the equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "4x = 92\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "divide both sides of the equation by 4 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 23\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you started with:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + y + z = 77 \n" ); document.write( "z = x - 5 \n" ); document.write( "y = 2z\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since x = 23, these equations became:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "24 + y + z = 77 \n" ); document.write( "z = 23 - 5 = 18 \n" ); document.write( "y = 2z = 2 * 18 = 36\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you have:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 23 \n" ); document.write( "y = 36 \n" ); document.write( "z = 18\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + y + z becomes 23 + 36 + 18 = 77 \n" ); document.write( "z = x - 5 becomes z = 23 - 5 = 18 \n" ); document.write( "y = 2z becomes y = 2 * 18 = 36\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solution looks good.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |