Question 977847
Find x and y so that x+y=s and xy=p for some constants s and p.
s is for sum and p is for product.  Your example uses s=121 and p=3528.


{{{y=s-x}}};
-
{{{x(s-x)=p}}}
{{{sx-x^2=p}}}
{{{-x^2+sx-p=0}}}
{{{x^2-sx+p=0}}}


You may expect that the quadratic left side is factorable, although possibly difficult to find.  You still can use  general formula for the solution.


{{{highlight(x=(s+- sqrt(s^2-4*p))/2)}}}, and you need the positive value for x.  Use it to find y.