Question 815212
The formula for the vertex is {{{ x[v] = -b/2a }}}
when the form of the equation is
{{{ f(x) = a*x^2 + b*x + c }}}
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{{{ f(x) = x^2 - 2b*x + 7 }}}
{{{ a = 1 }}}
{{{ b = -2b }}} ( different b's )
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So, 
{{{ x[v] = 6 }}}
{{{ 6 = (-(-2b)) / (2*1) }}}
{{{ 6 = (2b)/2 }}}
{{{ 2b = 12 }}}
{{{ b = 6 }}}
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So, the equation would be:
{{{ f(x) = x^2 - 2*6*x + 7 }}}
{{{ f(x) = x^2 - 12x + 7 }}}
Here's the plot:
{{{ graph( 400, 400, -2, 15, -30, 5, x^2 - 12x + 7 ) }}}
It looks like when {{{ x=6 }}}, {{{ y=-29 }}} or so
I'll check:
{{{ y = x^2 - 12x + 7 }}}
{{{ y = 6^2 -12*6 + 7 }}}
{{{ y = 36 - 72 + 7 }}}
{{{ y = -29 }}}
OK