document.write( "Question 249751: the vertex of
\n" ); document.write( "2x^2 + 8x + 1 is at what point \n" ); document.write( "

Algebra.Com's Answer #181849 by jsmallt9(3759) $\"\"$ $\"About$

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I assume the equation is
\n" ); document.write( " $\"y+=+2x%5E2+%2B+8x+%2B+1\"$ \n" ); document.write( "When the equation of a parabola is in the form $\"y+=+ax%5E2+%2B+bx+%2Bc\"$ , then the x coordinate of the vertex is $\"%28-b%29%2F2a\"$ . In your equation, the \"a\" is 2 and the \"b\" is 8, so the x coordinate of the vertex is
\n" ); document.write( " $\"%28-%288%29%29%2F2%282%29+=+%28-8%29%2F4+=+-2\"$

\n" ); document.write( "Now that we know the x coordinate of the vertex we can use the equation to figure out its y coordinate:
\n" ); document.write( " $\"y+=+2%28-2%29%5E2+%2B+8%28-2%29+%2B+1\"$
\n" ); document.write( " $\"y+=+2%284%29+%2B+8%28-2%29+%2B+1\"$
\n" ); document.write( " $\"y+=+8+%2B+%28-16%29+%2B+1\"$
\n" ); document.write( " $\"y+=+-7\"$

\n" ); document.write( "So the coordinates of the vertex are: (2, -7) \n" ); document.write( "

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