document.write( "Question 221042: What is the value of x when it's 4x squared + 8x + 4 = O? Can you show me how to solve it without using the quadratic formula? \n" ); document.write( "
Algebra.Com's Answer #165836 by jim_thompson5910(35256)\"\" \"About 
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We can solve this by factoring.\r
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\n" ); document.write( "\n" ); document.write( "\"4x%5E2%2B8x%2B4\" Start with the given expression.\r
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\n" ); document.write( "\n" ); document.write( "\"4%28x%5E2%2B2x%2B1%29\" Factor out the GCF \"4\".\r
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\n" ); document.write( "\n" ); document.write( "Now let's try to factor the inner expression \"x%5E2%2B2x%2B1\"\r
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\n" ); document.write( "\n" ); document.write( "Looking at the expression \"x%5E2%2B2x%2B1\", we can see that the first coefficient is \"1\", the second coefficient is \"2\", and the last term is \"1\".\r
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\n" ); document.write( "\n" ); document.write( "Now multiply the first coefficient \"1\" by the last term \"1\" to get \"%281%29%281%29=1\".\r
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\n" ); document.write( "\n" ); document.write( "Now the question is: what two whole numbers multiply to \"1\" (the previous product) and add to the second coefficient \"2\"?\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 \"1\" (the previous product).\r
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\n" ); document.write( "\n" ); document.write( "Factors of \"1\":\r
\n" ); document.write( "\n" ); document.write( "1\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 \"1\".\r
\n" ); document.write( "\n" ); document.write( "1*1 = 1
\n" ); document.write( "(-1)*(-1) = 1\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 \"2\":\r
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First NumberSecond NumberSum
111+1=2
-1-1-1+(-1)=-2
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\n" ); document.write( "\n" ); document.write( "From the table, we can see that the two numbers \"1\" and \"1\" add to \"2\" (the middle coefficient).\r
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\n" ); document.write( "\n" ); document.write( "So the two numbers \"1\" and \"1\" both multiply to \"1\" and add to \"2\"\r
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\n" ); document.write( "\n" ); document.write( "Now replace the middle term \"2x\" with \"x%2Bx\". Remember, \"1\" and \"1\" add to \"2\". So this shows us that \"x%2Bx=2x\".\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2Bhighlight%28x%2Bx%29%2B1\" Replace the second term \"2x\" with \"x%2Bx\".\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2%2Bx%29%2B%28x%2B1%29\" Group the terms into two pairs.\r
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\n" ); document.write( "\n" ); document.write( "\"x%28x%2B1%29%2B%28x%2B1%29\" Factor out the GCF \"x\" from the first group.\r
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\n" ); document.write( "\n" ); document.write( "\"x%28x%2B1%29%2B1%28x%2B1%29\" Factor out \"1\" 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( "\"%28x%2B1%29%28x%2B1%29\" Combine like terms. Or factor out the common term \"x%2B1\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B1%29%5E2\" Condense the terms.\r
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\n" ); document.write( "\n" ); document.write( "So \"4%28x%5E2%2B2x%2B1%29\" then factors further to \"4%28x%2B1%29%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "So \"4x%5E2%2B8x%2B4\" completely factors to \"4%28x%2B1%29%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "In other words, \"4x%5E2%2B8x%2B4=4%28x%2B1%29%5E2\".\r
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\n" ); document.write( "\n" ); document.write( "So \"4x%5E2%2B8x%2B4=0\" is equivalent to \"4%28x%2B1%29%5E2=0\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's solve \"4%28x%2B1%29%5E2=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"4%28x%2B1%29%5E2=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B1%29%5E2=%280%29%2F%284%29\" Divide both sides by \"4\".\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2B1%29%5E2=0\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B1=%22%22%2B-sqrt%280%29\" Take the square root of both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B1=sqrt%280%29\" or \"x%2B1=-sqrt%280%29\" Break up the \"plus/minus\" to form two equations.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B1=0\" or \"x%2B1=-0\" Take the square root of \"0\" to get \"0\".\r
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\n" ); document.write( "\n" ); document.write( "Since -0 is really 0, this means we have one equation: \"x%2B1=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=0-1\" Subtract \"1\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"x=-1\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So the only solution is \"x=-1\".
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