document.write( "Question 190256: Factor the trinomial\r
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Algebra.Com's Answer #142765 by jim_thompson5910(35256) $\"\"$ $\"About$

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\n" ); document.write( "\n" ); document.write( "Looking at the expression $\"z%5E2-3z%2B2\"$ , we can see that the first coefficient is $\"1\"$ , the second coefficient is $\"-3\"$ , and the last term is $\"2\"$ .\r
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\n" ); document.write( "\n" ); document.write( "Now multiply the first coefficient $\"1\"$ by the last term $\"2\"$ to get $\"%281%29%282%29=2\"$ .\r
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\n" ); document.write( "\n" ); document.write( "Now the question is: what two whole numbers multiply to $\"2\"$ (the previous product) and add to the second coefficient $\"-3\"$ ?\r
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\n" ); document.write( "\n" ); document.write( "To find these two numbers, we need to list all of the factors of $\"2\"$ (the previous product).\r
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\n" ); document.write( "\n" ); document.write( "Factors of $\"2\"$ :\r
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\n" ); document.write( "\n" ); document.write( "Note: list the negative of each factor. 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 $\"2\"$ .\r
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\n" ); document.write( "\n" ); document.write( "Now let's add up each pair of factors to see if one pair adds to the middle coefficient $\"-3\"$ :\r
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First Number	Second Number	Sum
1	2	1+2=3
-1	-2	-1+(-2)=-3

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\n" ); document.write( "\n" ); document.write( "From the table, we can see that the two numbers $\"-1\"$ and $\"-2\"$ add to $\"-3\"$ (the middle coefficient).\r
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\n" ); document.write( "\n" ); document.write( "So the two numbers $\"-1\"$ and $\"-2\"$ both multiply to $\"2\"$ and add to $\"-3\"$ \r
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\n" ); document.write( "\n" ); document.write( "Now replace the middle term $\"-3z\"$ with $\"-z-2z\"$ . Remember, $\"-1\"$ and $\"-2\"$ add to $\"-3\"$ . So this shows us that $\"-z-2z=-3z\"$ .\r
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\n" ); document.write( "\n" ); document.write( " $\"z%5E2%2Bhighlight%28-z-2z%29%2B2\"$ Replace the second term $\"-3z\"$ with $\"-z-2z\"$ .\r
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\n" ); document.write( "\n" ); document.write( " $\"%28z%5E2-z%29%2B%28-2z%2B2%29\"$ Group the terms into two pairs.\r
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\n" ); document.write( "\n" ); document.write( " $\"z%28z-1%29%2B%28-2z%2B2%29\"$ Factor out the GCF $\"z\"$ from the first group.\r
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\n" ); document.write( "\n" ); document.write( " $\"z%28z-1%29-2%28z-1%29\"$ Factor out $\"2\"$ from the second group. The goal of this step is to make the terms in the second parenthesis equal to the terms in the first parenthesis.\r
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\n" ); document.write( "\n" ); document.write( " $\"%28z-2%29%28z-1%29\"$ Combine like terms. Or factor out the common term $\"z-1\"$ \r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So $\"z%5E2-3z%2B2\"$ factors to $\"%28z-2%29%28z-1%29\"$ .\r
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\n" ); document.write( "\n" ); document.write( "Note: you can check the answer by FOILing $\"%28z-2%29%28z-1%29\"$ to get $\"z%5E2-3z%2B2\"$ or by graphing the original expression and the answer (the two graphs should be identical).
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