document.write( "Question 77056: z(5)=9,z(6)=12,z(7)=15,z(8)=18. If z = lny, find a formula for y in terms of x \n" ); document.write( "
Algebra.Com's Answer #55230 by Edwin McCravy(20056)\"\" \"About 
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document.write( "z(5)=9,z(6)=12,z(7)=15,z(8)=18. If z = lny, \r\n" );
document.write( "find a formula for y in terms of x.\r\n" );
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document.write( "9, 12, 15, 18 forms an arithmetic sequence \r\n" );
document.write( "with common difference = d = 3. So we make  \r\n" );
document.write( "lists of x, 3x, z(x) and 3x-z(x) \r\n" );
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document.write( " x  3x  z(x) 3x-z(x) \r\n" );
document.write( " 5  15   9     6\r\n" );
document.write( " 6  18  12     6\r\n" );
document.write( " 7  21  15     6\r\n" );
document.write( " 8  24  18     6\r\n" );
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document.write( "We see that 3x - z(x) = 6 in every case, so\r\n" );
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document.write( "            3x - z(x) = 6\r\n" );
document.write( "                -z(x) = -3x + 6\r\n" );
document.write( "                 z(x) = 3x - 6\r\n" );
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document.write( "Since z(x) = ln(y), y = ez(x) = e3x-6\r\n" );
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document.write( "or if you prefer, y = e3(x-2)\r\n" );
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document.write( "Edwin
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