Question 910423
You've got a mistake.
{{{n = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
In this case,
{{{a=4}}}
{{{b=-10}}}
{{{c=-104}}}
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{{{n = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
{{{n = (-(-10) +- sqrt( (-10)^2-4*4*(-104) ))/(2*4) }}} 
{{{n = (10 +- sqrt( 100+1664 ))/(8) }}} 
{{{n = (10 +- sqrt( 1764 ))/(8) }}}
{{{n = (10 +- 42)/(8) }}}
{{{n = (10 + 42)/(8) }}} and {{{n = (10 - 42)/(8) }}}
{{{n = (52)/(8) }}} and {{{n = (-32)/(8) }}}
{{{n = 13/2 }}} and {{{n = -4 }}}