mx(m-x)-m*n^2-n(n^2-x^2)=0
m^2x-mx^2-m*n^2-n^3+nx^2=0
(n-m)x^2+m^2x-(m+n)n^2=0
x1=(-m+(m^2+4n^2(n^2-m^2))^0.5)/(2(n-m))
=(-m+(m^2-4n^2m^2+4n^4)^0.5)/(2(n-m))
x2=(-m-(m^2+4n^2(n^2-m^2))^0.5)/(2(n-m))
=(-m-(m^2-4n^2m^2+4n^4)^0.5)/(2(n-m))