document.write( "Question 490208: K is between J and L JK=2x^2+3 KL=7x+4 JL=2x+10 Find JK\r
\n" ); document.write( "\n" ); document.write( "I have solved to 2x^2+5X=3, but that makes no sense and am lost. Thanks for any help.
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Algebra.Com's Answer #333951 by Theo(13342)\"\" \"About 
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K is between J and L
\n" ); document.write( "this means that JK + KL = JL\r
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\n" ); document.write( "\n" ); document.write( "JK is equal to 2x^2 + 3
\n" ); document.write( "KL is equal to 7x+4
\n" ); document.write( "JL is equal to 2x+10\r
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\n" ); document.write( "\n" ); document.write( "since JK + KL = JL, this means that:
\n" ); document.write( "2x^2 + 3 + 7x+4 = 2x+10\r
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\n" ); document.write( "\n" ); document.write( "you want to solve for x.
\n" ); document.write( "once you solve for x, then you can solve for the value of JK.\r
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\n" ); document.write( "\n" ); document.write( "your equation to work with is:
\n" ); document.write( "2x^2 + 3 + 7x + 4 = 2x + 10
\n" ); document.write( "subtract 2x from both sides of the equation and subtract 10 from both sides of the equation to get:
\n" ); document.write( "2x^2 + 3 + 7x + 4 - 2x - 10 = 0
\n" ); document.write( "combine like terms to get:
\n" ); document.write( "2x^2 + 5x - 3 = 0
\n" ); document.write( "this is a quadratic equation that can be solved for the value of x.
\n" ); document.write( "the factors to this equation are:
\n" ); document.write( "(2x - 1) * (x + 3) = 0
\n" ); document.write( "this equation is true if (2x - 1) = 0 or (x + 3) = 0 or both are equal to 0.
\n" ); document.write( "solving for 2x - 1 = 0 gets x = 1/2
\n" ); document.write( "solving for x + 3 = 0 gets x = -3\r
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\n" ); document.write( "\n" ); document.write( "since we are talking about the length of JK, KL, AND JL, then the length must be positive so the only answer that is acceptable is x = 1/2\r
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\n" ); document.write( "\n" ); document.write( "when x = 1/2, we get:\r
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\n" ); document.write( "\n" ); document.write( "JK = 2x^2 + 3 which results in JK = 3.5
\n" ); document.write( "KL = 7x + 4 which results in KL = 7.5
\n" ); document.write( "JL = 2x + 10 which results in JL = 11\r
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\n" ); document.write( "\n" ); document.write( "since JK + KL = JL, then we should get 11 = 11
\n" ); document.write( "JK + KL = 3.5 + 7.5 = 11
\n" ); document.write( "we're good.\r
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\n" ); document.write( "\n" ); document.write( "the value of x is confirmed as good which results in JK = 3.5 which answers the question.\r
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