document.write( "Question 356772: find the vertex of the x and y coordinate, line of symmetry and maximum of f(x)
\n" ); document.write( "f(x)=-2x^2+2x+7
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Algebra.Com's Answer #254738 by CharlesG2(834)\"\" \"About 
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find the vertex of the x and y coordinate, line of symmetry and maximum of f(x)
\n" ); document.write( "f(x)=-2x^2+2x+7\r
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\n" ); document.write( "\n" ); document.write( "f(x) = -2x^2 + 2x + 7, this is of form f(x) = ax^2 + bx + c
\n" ); document.write( "a = -2, a < 0, so parabola opens downwards\r
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\n" ); document.write( "\n" ); document.write( "f(x) = -2x^2 + 2x + 7 is standard form of the parabolic equation
\n" ); document.write( "converting to vertex form
\n" ); document.write( "f(x) = -2(x^2 - x) + 7
\n" ); document.write( "(-1/2)^2 = 1/4
\n" ); document.write( "-2 * 1/4 = -2/4 = -1/2
\n" ); document.write( "7 + 1/2 = 7 1/2 = 15/2
\n" ); document.write( "the above 3 lines were completing the square to get below line
\n" ); document.write( "f(x) = -2x^2 + 2x - 1/2 + 7 + 1/2 = -2(x^2 - x + 1/4) + 15/2
\n" ); document.write( "f(x) = -2(x - 1/2)^2 + 15/2\r
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\n" ); document.write( "\n" ); document.write( "this is now in vertex form of f(x) = a(x - h)^2 + k, where (h,k) is vertex\r
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\n" ); document.write( "\n" ); document.write( "vertex is (1/2,15/2)\r
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\n" ); document.write( "\n" ); document.write( "axis of symmetry -> x = h = 1/2\r
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\n" ); document.write( "\n" ); document.write( "maximum of f(x) since parabola opens downwards is k or 15/2\r
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