document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=2212>Question 2212</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How do you like no how to like factor- like if you have 6x squared plus 13x plus 5 you know that 5 and 1 work and 2 and 3 and 3 and 2 and all but how do you no which set of numbers you use in your equation? <BR>\n" );
document.write( " PLLLEEAASEEE help i have a test on thursday and i don't get this at all- thanks! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #921 by </B><A HREF=/tutors/aboutme.mpl?userid=longjonsilver><B>longjonsilver(2297)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=longjonsilver><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=longjonsilver><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=921\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2%2B5x%2B6 ALIGN=MIDDLE  ALT=\"x%5E2%2B5x%2B6\"   DISABLED_style= \"max-width:90%; height:auto;\" > factorises to (x+3)(x+2). This is found by finding 2 numbers that multiply to give the 6 and also add to give the 5.\r<BR>\n" );
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document.write( "Note however, that the <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2 ALIGN=MIDDLE  ALT=\"x%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > term has a coefficent of 1, so this \"look and see\" method of factorisation is fairly easy.\r<BR>\n" );
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document.write( "Factorisation becomes more tricky when the <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2 ALIGN=MIDDLE  ALT=\"x%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" > term has a coefficient not equal to 1, like your example, so you just have to do more mental work, that is all :-D.\r<BR>\n" );
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document.write( "So look at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6x%5E2+%2B+13x+%2B+5 ALIGN=MIDDLE  ALT=\"6x%5E2+%2B+13x+%2B+5\"   DISABLED_style= \"max-width:90%; height:auto;\" >. The first thing is that the solution will hopefully be either (6x..)(x..) or (3x..)(2x..), since both of these versions give the answer <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6x%5E2 ALIGN=MIDDLE  ALT=\"6x%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "So, we have to try both, i am afraid...no easier way :-(\r<BR>\n" );
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document.write( "One thing to make it easier however is that the \"c\" value is 5...so that narrows its possibilities right down to 1x5 straightaway, so we have 4 possible answers:\r<BR>\n" );
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document.write( "1. (6x + 5)(x  + 1) or<BR>\n" );
document.write( "2. (6x + 1)(x  + 5) or <BR>\n" );
document.write( "3. (3x + 5)(2x + 1) or <BR>\n" );
document.write( "4. (3x + 1)(2x + 5)\r<BR>\n" );
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document.write( "A quick mental check of multiplying out the brackets (just the x-term) gives...\r<BR>\n" );
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document.write( "1. 6x + 5x = 11 WRONG!<BR>\n" );
document.write( "2. 30x + x = 31x WRONG!<BR>\n" );
document.write( "3. 3x + 5x = 8x WRONG!<BR>\n" );
document.write( "4. 15x + 2x = 17x WRONG!\r<BR>\n" );
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document.write( "So all 4 are wrong so either, we cannot factorise \"easily\" and will have to use the quadratic formula OR (and i guess this is true) you have copied the question incorrectly!\r<BR>\n" );
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document.write( "I say this, since 15x MINUS 2x would give 13x, so i think the equation should be <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6x%5E2+%2B+13x+-+5 ALIGN=MIDDLE  ALT=\"6x%5E2+%2B+13x+-+5\"   DISABLED_style= \"max-width:90%; height:auto;\" > which will factorise to (3x - 1)(2x + 5).\r<BR>\n" );
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document.write( "Does that help?\r<BR>\n" );
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document.write( "jon. </SPAN>\n" );
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