#You can run these Python commands one by one at live.sympy.org.
#You can also get similar results from your calculator (if it has a CAS).

from sympy import *
l=var('l')
A=Matrix([[10-l,-1,-1],[-9,2-l,-9],[-1,-1,10+l]])
b=Matrix([[53],[-99],[44]])
u=simplify(A.inv()*b)
((x),(y),(z))=simplify(u*(l+9)*(l-11)*l)
print((x,y,z))
sol=solve(x**2+y**2-z**2,l)
print([N(s) for s in sol])
print(N(u.subs(l,sol[2])))
print(N(u.subs(l,sol[3])))
