Question 139522
I presume you want to find the zeros of the function.  Your problem is to find those values of x, say r and s, such that {{{g(r)=0}}} and {{{g(s)=0}}}.


{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} is the quadratic formula and is the solution to the general quadratic {{{ax^2+bx+c=0}}}


Since you want to find the values of x that make {{{g(x)=0}}}, set your polynomial equal to zero:  {{{x^2 + x + 12=0}}}


Now look at the general quadratic equation and compare it to your equation.  It should be clear that for your equation {{{a=1}}}, {{{b=1}}}, and {{{c=3}}}.


So all you need to do is substitute those values into the quadratic equation given above and do the arithmetic.  Remember that quadratics always have two roots, hence the 'plus or minus' sign in the numerator.