document.write( "Question 68854: 3. Take a look at the table below and write out an equation for f(x).
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Algebra.Com's Answer #49014 by Edwin McCravy(20056)\"\" \"About 
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document.write( "3.  Take a look at the table below and \r\n" );
document.write( "write out an equation for f(x).\r\n" );
document.write( "x    -2  -1  0  1  2\r\n" );
document.write( "f(x) -5  -2  1  4  7\r\n" );
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document.write( "Plot them:\r\n" );
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document.write( "They look like they all fall on a straight \r\n" );
document.write( "line, so pick any two of them and find the \r\n" );
document.write( "slope:\r\n" );
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document.write( "Say we pick the points (0,1) and (1,4)\r\n" );
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document.write( "Use the slope formula:\r\n" );
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document.write( "     y2 - y1\r\n" );
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document.write( "     x2 - x1\r\n" );
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document.write( "where (x1, y1) = (0, 1) and (x2, y2) = (1, 4)\r\n" );
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document.write( "     (4) - (1)     3     \r\n" );
document.write( "m = ——————————— = ——— = 3\r\n" );
document.write( "     (1) - (0)     1      \r\n" );
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document.write( "Now substitute in the point slope formula:\r\n" );
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document.write( "   y - y1 = m(x - x1)\r\n" );
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document.write( "   y - 1 = 3(x - 0)\r\n" );
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document.write( "   y - 1 = 3x\r\n" );
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document.write( "       y = 3x + 1 \r\n" );
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document.write( "Now replace \" y \" with the functional notation \" f(x) \"\r\n" );
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document.write( "    f(x) = 3x + 1\r\n" );
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document.write( "Edwin

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