document.write( "Question 617244: ab +bc+ ca , when a + b + c+12 and a*a = b*b +c*c =50 \n" ); document.write( "
Algebra.Com's Answer #388266 by KMST(5328)\"\" \"About 
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I believe you had a typo in your question. Maybe you had to evaluate ab + bc + ca, and were given as information that
\n" ); document.write( "a + b + c = 12 and a*a = b*b +c*c =50
\n" ); document.write( "(I'll write that last equation as \"a%2Aa=b%2Ab%2Bc%2Ac=50\")
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\n" ); document.write( "If that was the problem, we could start with the product \"%28a%2Bb%2Bc%29%28a%2Bb%2Bc%29\"
\n" ); document.write( "and apply the distributive property twice to get
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\n" ); document.write( "To simplify the writing, I would like to start omitting some of those asterisks and middle dot symbols for multiplication,
\n" ); document.write( "to be able to write \"ab\" instead of a*b or \"a%2Ab\", \"bc\" instead of \"b%2Ac\", and the like.
\n" ); document.write( "I would also apply the commutative property that says that
\n" ); document.write( "\"ab=a%2Ab=+b%2Aa=ba\", and similarly \"ac=ca\", and \"bc=cb\",
\n" ); document.write( "so that I can write all those products as the ab, bc, or ca in the formula that needs to be evaluated
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\n" ); document.write( "Next, I would rearrange the terms
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\n" ); document.write( "I would also group them to get together similar terms.
\n" ); document.write( "(I also want to group together the expressions that the problem gives values for).
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\n" ); document.write( "Now we have that
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\n" ); document.write( "Next, we replace the known values for \"a%2Bb%2Bc\" , \"a%2Aa\" and \"b%2Ab%2Bc%2Ac\"
\n" ); document.write( "\"12%2A12=50%2B50%2B%28%28ab%2Bbc%2Bca%29%2B%28ab%2Bbc%2Bca%29%29\" --> \"144=100%2B%28%28ab%2Bbc%2Bca%29%2B%28ab%2Bbc%2Bca%29%29\" --> \"144=100%2B2%28ab%2Bbc%2Bca%29\"
\n" ); document.write( "At this point, I first subtract 100 from the expressions on both sides of the equal sign:
\n" ); document.write( "\"144=100%2B2%28ab%2Bbc%2Bca%29\" --> \"144-100=100%2B2%28ab%2Bbc%2Bca%29-100\" --> \"44=2%28ab%2Bbc%2Bca%29\"
\n" ); document.write( "Then, I divide the expressions on both sides of the equal sign by 2:
\n" ); document.write( "\"44=2%28ab%2Bbc%2Bca%29\" --> \"44%2F2=2%28ab%2Bbc%2Bca%29%2F2\" --> \"22=ab%2Bbc%2Bca\"
\n" ); document.write( "\"highlight%28ab%2Bbc%2Bca=22%29\"
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