document.write( "Question 997336: If you know that -2 is a zero of f(x)=x^3+7x^2+4x-12, explain how to solve the equation x^3+7x^2+4x+12=0.
\n" ); document.write( "Also give an explanation to why x-2 is or is not a factor
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Algebra.Com's Answer #615486 by MathLover1(20850)\"\" \"About 
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\"f%28x%29=x%5E3%2B7x%5E2%2B4x-12\"\r
\n" ); document.write( "\n" ); document.write( "if \"x%5B1%5D=-2\" is a zero, means \"f%28x%29=x%5E3%2B7x%5E2%2B4x-12\" is divisible by \"x-x%5B1%5D=x-%28-2%29=x%2B2\"->an explanation to why \"x-2\" is not a factor\r
\n" ); document.write( "\n" ); document.write( "use long division:\r
\n" ); document.write( "\n" ); document.write( "---------(\"x%5E2%2B5x-6\"
\n" ); document.write( "\"x%2B2\"|\"x%5E3%2B7x%5E2%2B4x-12\"
\n" ); document.write( "----------\"x%5E3%2B2x%5E2\".......subtract
\n" ); document.write( "------------\"0%2B5x%5E2\"......add \"4x\"
\n" ); document.write( "------------- \"5x%5E2%2B4x\"......
\n" ); document.write( "------------- \"5x%5E2%2B10x\".......subtract
\n" ); document.write( "-------------- \"0-6x\".......add \"-12\"
\n" ); document.write( "--------------- \"-6x-12\".......
\n" ); document.write( "--------------- \"-6x-12\".......subtract
\n" ); document.write( "----------------- \"0\".......reminder\r
\n" ); document.write( "\n" ); document.write( "so, now we know two factors of given polynomial, and they are \"x%2B2\" and \"x%5E2%2B5x-6\"\r
\n" ); document.write( "\n" ); document.write( "so, you have
\n" ); document.write( "\"f%28x%29=%28x%2B2%29%28x%5E2%2B5x-6%29\" ...now we can factor \"x%5E2%2B5x-6\" too\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=%28x%2B2%29%28x%5E2%2B6x-x-6%29\"\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=%28x%2B2%29%28%28x%5E2%2B6x%29-%28x%2B6%29%29\"\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=%28x%2B2%29%28x%28x%2B6%29-%28x%2B6%29%29\"\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=%28x%2B2%29%28x-1%29%28x%2B6%29\"\r
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\n" ); document.write( "\n" ); document.write( "so, zeros are:\r
\n" ); document.write( "\n" ); document.write( "if \"0=%28x%2B2%29\"=>\"x=-2\"
\n" ); document.write( "if \"0=%28x-1%29\"=>\"x=1\"
\n" ); document.write( "if \"0=%28x%2B6%29\"=>\"x=-6\"\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+600%2C+600%2C+-10%2C+10%2C+-15%2C+15%2C+x%5E3%2B7x%5E2%2B4x-12%29+\"\r
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