Question 80924
the quadratic formula is {{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
in your equation a=1 b=-12 c=-3
substitute these values in formula
{{{x=(12+-sqrt(144+12))/2=(12+-sqrt(156))/2=(12+- 2sqrt(39))/2=6+-sqrt(39)}}}