document.write( "Question 815212: For which value of b will the quadratic function below have an x-value of 6 at the minimum ? \r
\n" ); document.write( "\n" ); document.write( "f(x)=x^2-2bx+7 \r
\n" ); document.write( "\n" ); document.write( "Any help will be great, thanks.
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Algebra.Com's Answer #490769 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
The formula for the vertex is \"+x%5Bv%5D+=+-b%2F2a+\"
\n" ); document.write( "when the form of the equation is
\n" ); document.write( "\"+f%28x%29+=+a%2Ax%5E2+%2B+b%2Ax+%2B+c+\"
\n" ); document.write( "----------------------
\n" ); document.write( "\"+f%28x%29+=+x%5E2+-+2b%2Ax+%2B+7+\"
\n" ); document.write( "\"+a+=+1+\"
\n" ); document.write( "\"+b+=+-2b+\" ( different b's )
\n" ); document.write( "-----------------------
\n" ); document.write( "So,
\n" ); document.write( "\"+x%5Bv%5D+=+6+\"
\n" ); document.write( "\"+6+=+%28-%28-2b%29%29+%2F+%282%2A1%29+\"
\n" ); document.write( "\"+6+=+%282b%29%2F2+\"
\n" ); document.write( "\"+2b+=+12+\"
\n" ); document.write( "\"+b+=+6+\"
\n" ); document.write( "----------
\n" ); document.write( "So, the equation would be:
\n" ); document.write( "\"+f%28x%29+=+x%5E2+-+2%2A6%2Ax+%2B+7+\"
\n" ); document.write( "\"+f%28x%29+=+x%5E2+-+12x+%2B+7+\"
\n" ); document.write( "Here's the plot:
\n" ); document.write( "\"+graph%28+400%2C+400%2C+-2%2C+15%2C+-30%2C+5%2C+x%5E2+-+12x+%2B+7+%29+\"
\n" ); document.write( "It looks like when \"+x=6+\", \"+y=-29+\" or so
\n" ); document.write( "I'll check:
\n" ); document.write( "\"+y+=+x%5E2+-+12x+%2B+7+\"
\n" ); document.write( "\"+y+=+6%5E2+-12%2A6+%2B+7+\"
\n" ); document.write( "\"+y+=+36+-+72+%2B+7+\"
\n" ); document.write( "\"+y+=+-29+\"
\n" ); document.write( "OK
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