document.write( "Question 78943: 12X^2-41X+24 \n" ); document.write( "
Algebra.Com's Answer #56661 by mathdoc314(58)\"\" \"About 
You can put this solution on YOUR website!
That is not a problem. It is an expression. There are many things that can be done with an expression. Next time I hope you will ask the question more completely and clearly!\r
\n" ); document.write( "\n" ); document.write( "Since you are letting me guess what is supposed to be done with it, I could graph it or solve for it = 0, but I think maybe you want me to factor it\r
\n" ); document.write( "\n" ); document.write( "\"+12+x%5E2+-+41+x+%2B+24+\"\r
\n" ); document.write( "\n" ); document.write( "This is going to be \"+%28ax+%2B+b%29+%28cx+%2B+d%29+\" \r
\n" ); document.write( "\n" ); document.write( "It multiplies out as \"+ac+%2A+x%5E2+%2B+%28a%2Ad+%2B+b%2Ac%29+x+%2B+%28b%2Ad%29+\"
\n" ); document.write( "This must be equal to \"+12+x%5E2+-+41+x+%2B+24+\"
\n" ); document.write( "Therefore it must be \"+ac=12+\", \"%28a%2Ad+%2B+b%2Ac%29+=+-41\", and \"+%28b%2Ad%29+=+24+\".\r
\n" ); document.write( "\n" ); document.write( "and the goal is to discover right numbers to use for a, b, c, d.
\n" ); document.write( "I will try to find an answer with whole numbers (no fractions or square roots yet).\r
\n" ); document.write( "\n" ); document.write( "a*c = 12
\n" ); document.write( "some possibilities are
\n" ); document.write( "(a=1,c=12), (a=2,c=6), (a=3,c=4), (a=4,c=3), (a=6,c=2), or (a=12, c=1). \r
\n" ); document.write( "\n" ); document.write( "b*d = 24
\n" ); document.write( "some possibilities are
\n" ); document.write( "(b=-1,d=-24), (b=-2,d=-12), (b=-3,d=-8), (b=-4,d=-6)\r
\n" ); document.write( "\n" ); document.write( "The next goal is to find the right combination of those possibilities to get a*d + b*c = -41 \r
\n" ); document.write( "\n" ); document.write( "This can be done slowly by trying out a lot of combinations, but then you probably get tired of it and hopefully notice some patterns.\r
\n" ); document.write( "\n" ); document.write( "What has to happen to get -41\r
\n" ); document.write( "\n" ); document.write( "One thing is that a*d has to be odd or b*c has to be odd. This eliminates a lot of combinations. You can't have a and c both be even, and you can't have b and d both be even. Also you cant have a big number for a and d at the same time because it gets too far over -41 if you have things like 12*8 in it.\r
\n" ); document.write( "\n" ); document.write( "It turns out -41 is the smallest odd term you can get\r
\n" ); document.write( "\n" ); document.write( "Here are some of the details\r
\n" ); document.write( "\n" ); document.write( "You can work with these:(a=1,c=12), (a=3,c=4), (a=4,c=3), (a=12, c=1)
\n" ); document.write( "and (b=-1,d=-24), (b=-3,d=-8)\r
\n" ); document.write( "\n" ); document.write( "(a=4,c=3,b=-1,d=-24) -> ad+bc = -96-3 = -99
\n" ); document.write( "(a=4,c=3,b=-3,d=-8) -> ad+bc = -32 - 9 = -41 <-- this one is the answer
\n" ); document.write( "(a=12,c=1,b=-1,d=-24) -> ad+bd = -288 - 1 = -289
\n" ); document.write( "(a=12,c=1,b=-3,d=-8) -> ad+bd = -96 - 3 = -99\r
\n" ); document.write( "\n" ); document.write( "So it factors as \"+%284x+-+3%29%283x+-+8%29+=+%2812x%5E2+-+41+x+%2B+24%29+\" and I am glad that is over. There are faster answers like completing the square and the quadratic formula. I hope this is the question you wanted to ask. Next time please say what you want the tutor to do.\r
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