document.write( "Question 103749This question is from textbook Precalculus A GRAPHING APPROACH
\n" ); document.write( ": My problem is if the vertex of f(x)=x^2+bx+c is at (2,4), find b and c. \n" ); document.write( "

Algebra.Com's Answer #75420 by edjones(8007) $\"\"$ $\"About$

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$\"f%5Bx%5D=a%28x-h%29%5E2%2Bk\"$ Standard form of the quadratic equation $\"x%3C%3E0\"$
\n" ); document.write( "The vertex point is (h,k).
\n" ); document.write( "h=2 k=4
\n" ); document.write( "f[x]=a(x-2)^2+4
\n" ); document.write( "=x^2-4x+4+4 (let a=1)
\n" ); document.write( "=x^2-4x+8
\n" ); document.write( "So, b=-4 and c=8
\n" ); document.write( "Ed
\n" ); document.write( " $\"graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E2-4x%2B8%29\"$ \n" ); document.write( "

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