document.write( "Question 257119: 4x^3+8x^2-12x \n" ); document.write( "
Algebra.Com's Answer #189264 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "\"4x%5E3%2B8x%5E2-12x\" Start with the given expression\r
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\n" ); document.write( "\n" ); document.write( "\"4x%28x%5E2%2B2x-3%29\" Factor out the GCF \"4x\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's focus on the inner expression \"x%5E2%2B2x-3\"\r
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\n" ); document.write( "\n" ); document.write( "Looking at \"x%5E2%2B2x-3\" we can see that the first term is \"x%5E2\" and the last term is \"-3\" where the coefficients are 1 and -3 respectively.\r
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\n" ); document.write( "\n" ); document.write( "Now multiply the first coefficient 1 and the last coefficient -3 to get -3. Now what two numbers multiply to -3 and add to the middle coefficient 2? Let's list all of the factors of -3:\r
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\n" ); document.write( "\n" ); document.write( "Factors of -3:\r
\n" ); document.write( "\n" ); document.write( "1,3\r
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\n" ); document.write( "\n" ); document.write( "-1,-3 ...List the negative factors as well. This will allow us to find all possible combinations\r
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\n" ); document.write( "\n" ); document.write( "These factors pair up and multiply to -3\r
\n" ); document.write( "\n" ); document.write( "(1)*(-3)\r
\n" ); document.write( "\n" ); document.write( "(-1)*(3)\r
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\n" ); document.write( "\n" ); document.write( "note: remember, the product of a negative and a positive number is a negative number\r
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\n" ); document.write( "\n" ); document.write( "Now which of these pairs add to 2? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to 2\r
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First NumberSecond NumberSum
1-31+(-3)=-2
-13-1+3=2
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\n" ); document.write( "\n" ); document.write( "From this list we can see that -1 and 3 add up to 2 and multiply to -3\r
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\n" ); document.write( "\n" ); document.write( "Now looking at the expression \"x%5E2%2B2x-3\", replace \"2x\" with \"-x%2B3x\" (notice \"-x%2B3x\" combines back to \"2x\". So it is equivalent to \"2x\")\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2Bhighlight%28-x%2B3x%29-3\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's factor \"x%5E2-x%2B3x-3\" by grouping:\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-x%29%2B%283x-3%29\" Group like terms\r
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\n" ); document.write( "\n" ); document.write( "\"x%28x-1%29%2B3%28x-1%29\" Factor out the GCF of \"x\" out of the first group. Factor out the GCF of \"3\" out of the second group\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B3%29%28x-1%29\" Since we have a common term of \"x-1\", we can combine like terms\r
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\n" ); document.write( "\n" ); document.write( "So \"x%5E2-x%2B3x-3\" factors to \"%28x%2B3%29%28x-1%29\"\r
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\n" ); document.write( "\n" ); document.write( "So this also means that \"x%5E2%2B2x-3\" factors to \"%28x%2B3%29%28x-1%29\" (since \"x%5E2%2B2x-3\" is equivalent to \"x%5E2-x%2B3x-3\")\r
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\n" ); document.write( "\n" ); document.write( "So our expression goes from \"4x%28x%5E2%2B2x-3%29\" and factors further to \"4x%28x%2B3%29%28x-1%29\"\r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So \"4x%5E3%2B8x%5E2-12x\" factors to \"4x%28x%2B3%29%28x-1%29\"\r
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