document.write( "Question 1083261: I just learned how to solve quadratic equations by completing the square and my book throws this doozy in a section called \"Challenge\", can this be solved by completing the square? Are there more than one way to solve it?\r
\n" ); document.write( "\n" ); document.write( "Solve for x in terms of a.\r
\n" ); document.write( "\n" ); document.write( "3x^2+ax^2=9x+9a
\n" ); document.write( "

Algebra.Com's Answer #697273 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
Some (not all) quadratic equation can be solved by factoring.
\n" ); document.write( "Every quadratic equation can be solved by completing the square,
\n" ); document.write( "and every quadratic equation can be solved by using the quadratic formula.
\n" ); document.write( "People usually resort to the quadratic formula,
\n" ); document.write( "but professor Peter Alfeld of the university of Utah
\n" ); document.write( "believes we should complete squares.
\n" ); document.write( "I use what comes easier. When factoring works, it may be easier.
\n" ); document.write( "
\n" ); document.write( "\"3x%5E2%2Bax%5E2=9x%2B9a\"
\n" ); document.write( "\"%283%2Ba%29x%5E2-9x=9a\"
\n" ); document.write( "Maybe dividing everything by \"%283%2Ba%29\" at this point would be easier.
\n" ); document.write( "Of course, we will have to add \"a%3C%3E-3\" as a requirement to any solution we find as a function of a.
\n" ); document.write( "\"x%5E2-%289%2F%283%2Ba%29%29x=9a%2F%283%2Ba%29\"
\n" ); document.write( "
\n" ); document.write( "\"%28x-9%2F%282a%2B6%29%29%5E2=9a%2F%283%2Ba%29%2B%289%2F%282%283%2Ba%29%29%29%5E2\"
\n" ); document.write( "\"%28x-9%2F%282a%2B6%29%29%5E2\"\"%22=%22\"\"9a%284%28a%2B3%29%29%2F%282a%2B6%29%5E2\"\"%22%2B%22\"\"9%5E2%2F%282a%2B6%29%5E2\"
\n" ); document.write( "\"%28x-9%2F%282a%2B6%29%29%5E2\"\"%22=%22\"\"%289%284a%5E2%2B12%29%2B81%29%2F%282a%2B6%29%5E2\"
\n" ); document.write( "\"%28x-9%2F%282a%2B6%29%29%5E2\"\"%22=%22\"\"9%284a%5E2%2B12a%2B9%29%2F%282a%2B6%29%5E2\"
\n" ); document.write( "\"%28x-9%2F%282a%2B6%29%29%5E2\"\"%22=%22\"\"9%282a%2B3%29%5E2%2F%282a%2B6%29%5E2\"
\n" ); document.write( "\"x=9%2F%282a%2B6%29+%2B-+3%282a%2B3%29%2F%282a%2B6%29\"
\n" ); document.write( "\"x=%289+%2B-+%286a%2B9%29%29%2F%282a%2B6%29\"
\n" ); document.write( "So, the two solutions are
\n" ); document.write( "\"x%5B1%5D=%286a%2B18%29%2F%282a%2B6%29=3\" and \"x%5B2%5D=6a%2F%282a%2B6%29=3a%2F%28a%2B3%29\" if \"a%3C%3E-3\"
\n" ); document.write( "
\n" ); document.write( "WAIT!
\n" ); document.write( "Why did we not realize that we could solve by factoring?
\n" ); document.write( "\"3x%5E2%2Bax%5E2=9x%2B9a\"
\n" ); document.write( "\"ax%5E2-9a%2B3x%5E2-9x=0\"
\n" ); document.write( "\"3x%28x-3%29=a%289-x%5E2%29\"
\n" ); document.write( "\"a%28x%5E2-9%29%2B3x%28x-3%29=0\"
\n" ); document.write( "\"a%28x%2B3%29%28x-3%29%2B3x%28x-3%29=0\"
\n" ); document.write( "\"%28a%28x%2B3%29%2B3x%29%28x-3%29=0\"
\n" ); document.write( "\"%28ax%2B3a%2B3x%29%28x-3%29=0\"
\n" ); document.write( "\"%28%28a%2B3%29x-3a%29%28x-3%29=0\"
\n" ); document.write( "At this point, either \"x-3=0\" ---> \"x=3\" , or
\n" ); document.write( "\"%28a%2B3%29x-3a=0\" ---> \"x=3a%2F%28a%2B3%29\" as long as \"a%3C%3E-3\" .
\n" ); document.write( "
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