document.write( "Question 254011: What is a function that has the values f(1)=8 and f(7)=-10 \n" ); document.write( "
Algebra.Com's Answer #186344 by jim_thompson5910(35256)\"\" \"About 
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Since f(1)=8 and f(7)=-10, this means that the line goes through the points (1,8) and (7,-10)\r
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\n" ); document.write( "\n" ); document.write( "First let's find the slope of the line through the points and \r
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\n" ); document.write( "\n" ); document.write( "Note: is the first point . So this means that \"x%5B1%5D=1\" and \"y%5B1%5D=8\".\r
\n" ); document.write( "\n" ); document.write( "Also, is the second point . So this means that \"x%5B2%5D=7\" and \"y%5B2%5D=-10\".\r
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\n" ); document.write( "\n" ); document.write( "\"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula.\r
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\n" ); document.write( "\n" ); document.write( "\"m=%28-10-8%29%2F%287-1%29\" Plug in \"y%5B2%5D=-10\", \"y%5B1%5D=8\", \"x%5B2%5D=7\", and \"x%5B1%5D=1\"\r
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\n" ); document.write( "\n" ); document.write( "\"m=%28-18%29%2F%287-1%29\" Subtract \"8\" from \"-10\" to get \"-18\"\r
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\n" ); document.write( "\n" ); document.write( "\"m=%28-18%29%2F%286%29\" Subtract \"1\" from \"7\" to get \"6\"\r
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\n" ); document.write( "\n" ); document.write( "\"m=-3\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "So the slope of the line that goes through the points and is \"m=-3\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's use the point slope formula:\r
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\n" ); document.write( "\n" ); document.write( "\"y-y%5B1%5D=m%28x-x%5B1%5D%29\" Start with the point slope formula\r
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\n" ); document.write( "\n" ); document.write( "\"y-8=-3%28x-1%29\" Plug in \"m=-3\", \"x%5B1%5D=1\", and \"y%5B1%5D=8\"\r
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\n" ); document.write( "\n" ); document.write( "\"y-8=-3x%2B-3%28-1%29\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"y-8=-3x%2B3\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=-3x%2B3%2B8\" Add 8 to both sides. \r
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\n" ); document.write( "\n" ); document.write( "\"y=-3x%2B11\" Combine like terms. \r
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\n" ); document.write( "\n" ); document.write( "\"y=-3x%2B11\" Simplify\r
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\n" ); document.write( "\n" ); document.write( "So the equation that goes through the points and is \"y=-3x%2B11\"\r
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\n" ); document.write( "\n" ); document.write( "This means that the function is \"f%28x%29=-3x%2B11\" (replace 'y' with f(x))\r
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\n" ); document.write( "\n" ); document.write( " Notice how the graph of \"y=-3x%2B11\" goes through the points and . So this visually verifies our answer.\r
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\n" ); document.write( " Graph of \"y=-3x%2B11\" through the points and \r
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