Check under Tools Options Display Typesetting level to see if it is set to extended.  

Interesting problem.  I found this method in the RealDomain help page.

restart;

n:=3;m:=2;
eqx:=x^(n/m)=a;
use RealDomain in (maple_sol:=solve(eqx,[x]))[] end use;  #also tried solve()
F:=map(X->eval(eqx,X),maple_sol);
map(X->evalb(X),F);
                             n := 3

                             m := 2

                               (3/2)    
                       eqx := x      = a

                          [     (2/3)]
                          [x = a     ]

                          F := [a = a]

                             [true]

This is rather similar to the 1st question I asked on MaplePrimes. I just happened to look at it today

Dual sum loop with a condition - MaplePrimes  

Download A_2024-03-15_Sum_with_Condition.mw

This is a way using seq

M := Matrix(4, 4, [[m[1, 1], m[1, 2], m[1, 3], m[1, 4]], 
                   [m[2, 1], m[2, 2], m[2, 3], m[2, 4]],
                   [m[3, 1], m[3, 2], m[3, 3], m[3, 4]],
                   [m[4, 1], m[4, 2], m[4, 3], m[4, 4]]]);

L:=[seq(M[1 .. 4, i], i = 1 .. 4)];

whattype(L[3]);

I am sure there are more direct ways.1st, I changed you numbers just to see if this works more generally. Works with you numbers too

a:=evalf(1119.8*21/101)
                        a := 232.8297030

b:=trunc(a)
                            b := 232

c:=evalf(a-b)
                         c := 0.8297030

d:=evalf(c,2)
                           d := 0.83

b+d
                             232.83

with your numbers
a:=evalf(3*21/100,3);
                           a := 0.630

b:=trunc(a)
                             b := 0

c:=evalf(a-b)
                           c := 0.630

d:=evalf(c,2)
                           d := 0.63

b+d
                              0.63

Your code has so many errors. Are you typing it in a text editor? Hard to see how you could enter that much code in maple and not notice or find errors along the way.

This runs but I cannot verify you logic.

I used the VS code editor to find the errors. and maplemint That might help you.

Cong:=proc(n)
 local  a,b,An,Bn,Cn,Dn:
if n mod 2 = 1  then  
  An:=0:   
  Bn:=0:    
  for a from (round(-sqrt(n/(2)))) to round(sqrt(n/(2)) ) do           
     for b  from (round(-sqrt(n)) )to round(sqrt(n) )do                
          if is( (sqrt(n-2*a^(2)-b^(2)) )/(32),integer  ) then 
               An:=An+1 ;               
             elif is((sqrt(n-2*a^(2)-b^(2)) )/(8) ,integer )  then                   
               Bn:=Bn+1 ;
          end if:          
     end do: 
  end do:
 end if; 
if 2*An=Bn  then
    print(True); 
  else 
   print(False);
end if; 
if n mod 2 = 0 then
    Cn:=0: 
    Dn:=0:
end if;          
for a  from (round(-sqrt(n/(8)))) to round(sqrt(n/(8)) ) do          
    for b  from (round(-sqrt(n/(2)))) to round(sqrt(n/(2))) do                
        if is((sqrt(n/(2)-4*a^(2)-b^(2)) )/(32), integer   ) then                  
              Cn:=Cn+1 ;               
          elif is((sqrt(n/(2)-4*a^(2)-b^(2)) )/(8) ,integer) then
            Dn:=Dn+1 ;
        end if:
    end do: 
end do:  
if 2*Cn=Dn then
    print("True");  
  else  
    print("False");
end if;  
end proc;

maplemint(Cong);
Cong(108);

If I am intrepetering things correctly.  Your

diff((z - zA)*(z - zB)*(z - zC), z)*I);   # I removed semicolin inside brackets

gives a 2nd order polynomial (quadratic)   .say it is Q(Z)    Why have you multiplied the whole diff eqn. by I 

solve(Q(z) , z ,explicit)   #gives two roots which are supposed to be the focii of the ellipse.

Look on Marden's theorem - Wikipedia

This is a really useful procedure I found here on Primes  years ago. Called factrix. though in this case it pulls out (-1/2) instead of (1/2)
Edit:- the link to the reference to factrix  How do I extract common factors in a matrix? - MaplePrimes

[moderator: Copyrighted code removed. Source is factrix by Robert Israel, part of his Maple Advisor Database.]

You have to expand the equation. 

if  expand((x+1)^2=x^2+2*x+1) then print(1) else print(0) fi

or

if  expand((x+1)^2)=x^2+2*x+1 then print(1) else print(0) fi

I parameterised the points on the ellipse. I made them projective points [x,y,1] in the form of vectors. Reason the equation of the  line through two projective points is the Cross Product of the two points as another vector . P1 X P2  = L12 Now the intersect point of two lines as vectors is L1 X L2= Pintersect.

A line in vector form <a , b, c>   represents a*x + b*y + c=0

The use of factrix by @Robert B. Isreal  reduces the projective vectors, as in projective geometry vectors can be scaled without changing the answers.

Edit:- Correction.  Replece this into the document.  The intersection points were scaled incorrectly.

The 3 collinear points

for i to 3 do
    pPint || i := convert(Pint || i[1 .. 2]/Pint || i[3], list);
    eval(pPint || i, pramsplot);
    evalf(%);
end do;

Download 2023-12-23_A_Pascal_Conic_parameterised.mw

You basically have a 5th order polynomail in h. In general there is no explicit solution for a 5th order or higher polynomial.

I asked the same question a couple on months age

@C_R answered it as follows

inserts a new execution group before the cursor.

For pasted text you could try F3 to split the text at the postition of the cursor.

from the menu should also work.

Here are two possible ways assuming I have understood you question correctly. I renamed your list to l to avoid confusion.

Download 3a.mw

Square brackets are incorrect use parenthesis ()

1/2*int(D__11*diff(w, x, x)^2 + 2*D__12*diff(w, x, x)*diff(w, y, y) + 4*D[66]*diff(w, x, y)^2 + D[22]*diff(w, y, y)^2 - 2*q*w, [x = 0 .. b, y = 0 .. a])

I got 

(((144*D__11*c[1]^2)/(5*a^8*b^3) - 72*D__11*c[1]^2/(a^7*b^4) + 64*D__11*c[1]^2/(a^6*b^5) - 24*D__11*c[1]^2/(a^5*b^6) + 4*D__11*c[1]^2/(a^4*b^7))*a^9)/18 + ((-(576*D__11*c[1]^2)/(5*a^8*b^2) + 288*D__11*c[1]^2/(a^7*b^3) - 256*D__11*c[1]^2/(a^6*b^4) + 96*D__11*c[1]^2/(a^5*b^5) - 16*D__11*c[1]^2/(a^4*b^6))*a^8)/16 + ((((288*D__12*c[1]^2/(a^8*b^8) + 1024*D[66]*c[1]^2/(a^8*b^8))*b^7)/7 + ((-864*D__12*c[1]^2/(a^7*b^8) - 3072*D[66]*c[1]^2/(a^7*b^8))*b^6)/6 + ((864*D__11*c[1]^2/(a^8*b^6) + 912*D__12*c[1]^2/(a^6*b^8) + 3328*D[66]*c[1]^2/(a^6*b^8))*b^5)/5 + ((-1728*D__11*c[1]^2/(a^7*b^6) - 384*D__12*c[1]^2/(a^5*b^8) - 1536*D[66]*c[1]^2/(a^5*b^8))*b^4)/4 + ((1152*D__11*c[1]^2/(a^6*b^6) + 48*D__12*c[1]^2/(a^4*b^8) + 256*D[66]*c[1]^2/(a^4*b^8))*b^3)/3 - 144*D__11*c[1]^2/(a^5*b^4) + 24*D__11*c[1]^2/(a^4*b^5))*a^7)/14 + ((((-864*D__12*c[1]^2/(a^8*b^7) - 3072*D[66]*c[1]^2/(a^8*b^7))*b^7)/7 + ((2592*D__12*c[1]^2/(a^7*b^7) + 9216*D[66]*c[1]^2/(a^7*b^7))*b^6)/6 + ((-576*D__11*c[1]^2/(a^8*b^5) - 2736*D__12*c[1]^2/(a^6*b^7) - 9984*D[66]*c[1]^2/(a^6*b^7))*b^5)/5 + ((1152*D__11*c[1]^2/(a^7*b^5) + 1152*D__12*c[1]^2/(a^5*b^7) + 4608*D[66]*c[1]^2/(a^5*b^7))*b^4)/4 + ((-768*D__11*c[1]^2/(a^6*b^5) - 144*D__12*c[1]^2/(a^4*b^7) - 768*D[66]*c[1]^2/(a^4*b^7))*b^3)/3 + 96*D__11*c[1]^2/(a^5*b^3) - 16*D__11*c[1]^2/(a^4*b^4))*a^6)/12 + ((16*D[22]*c[1]^2*b/a^8 - 72*D[22]*c[1]^2/a^7 + ((912*D__12*c[1]^2/(a^8*b^6) + 3328*D[66]*c[1]^2/(a^8*b^6) + 864*D[22]*c[1]^2/(a^6*b^8))*b^7)/7 + ((-2736*D__12*c[1]^2/(a^7*b^6) - 9984*D[66]*c[1]^2/(a^7*b^6) - 576*D[22]*c[1]^2/(a^5*b^8))*b^6)/6 + ((144*D__11*c[1]^2/(a^8*b^4) + 2888*D__12*c[1]^2/(a^6*b^6) + 10816*D[66]*c[1]^2/(a^6*b^6) + 144*D[22]*c[1]^2/(a^4*b^8) - 2*q*c[1]/(a^4*b^4))*b^5)/5 + ((-288*D__11*c[1]^2/(a^7*b^4) - 1216*D__12*c[1]^2/(a^5*b^6) - 4992*D[66]*c[1]^2/(a^5*b^6) + 4*q*c[1]/(a^3*b^4))*b^4)/4 + ((192*D__11*c[1]^2/(a^6*b^4) + 152*D__12*c[1]^2/(a^4*b^6) + 832*D[66]*c[1]^2/(a^4*b^6) - 2*q*c[1]/(a^2*b^4))*b^3)/3 - 24*D__11*c[1]^2/(a^5*b^2) + 4*D__11*c[1]^2/(a^4*b^3))*a^5)/10 + ((-32*D[22]*c[1]^2*b^2/a^8 + 144*D[22]*c[1]^2*b/a^7 + ((-384*D__12*c[1]^2/(a^8*b^5) - 1536*D[66]*c[1]^2/(a^8*b^5) - 1728*D[22]*c[1]^2/(a^6*b^7))*b^7)/7 + ((1152*D__12*c[1]^2/(a^7*b^5) + 4608*D[66]*c[1]^2/(a^7*b^5) + 1152*D[22]*c[1]^2/(a^5*b^7))*b^6)/6 + ((-1216*D__12*c[1]^2/(a^6*b^5) - 4992*D[66]*c[1]^2/(a^6*b^5) - 288*D[22]*c[1]^2/(a^4*b^7) + 4*q*c[1]/(a^4*b^3))*b^5)/5 + ((512*D__12*c[1]^2/(a^5*b^5) + 2304*D[66]*c[1]^2/(a^5*b^5) - 8*q*c[1]/(a^3*b^3))*b^4)/4 + ((-64*D__12*c[1]^2/(a^4*b^5) - 384*D[66]*c[1]^2/(a^4*b^5) + 4*q*c[1]/(a^2*b^3))*b^3)/3)*a^4)/8 + (((64*D[22]*c[1]^2*b^3)/(3*a^8) - 96*D[22]*c[1]^2*b^2/a^7 + ((48*D__12*c[1]^2/(a^8*b^4) + 256*D[66]*c[1]^2/(a^8*b^4) + 1152*D[22]*c[1]^2/(a^6*b^6))*b^7)/7 + ((-144*D__12*c[1]^2/(a^7*b^4) - 768*D[66]*c[1]^2/(a^7*b^4) - 768*D[22]*c[1]^2/(a^5*b^6))*b^6)/6 + ((152*D__12*c[1]^2/(a^6*b^4) + 832*D[66]*c[1]^2/(a^6*b^4) + 192*D[22]*c[1]^2/(a^4*b^6) - 2*q*c[1]/(a^4*b^2))*b^5)/5 + ((-64*D__12*c[1]^2/(a^5*b^4) - 384*D[66]*c[1]^2/(a^5*b^4) + 4*q*c[1]/(a^3*b^2))*b^4)/4 + ((8*D__12*c[1]^2/(a^4*b^4) + 64*D[66]*c[1]^2/(a^4*b^4) - 2*q*c[1]/(a^2*b^2))*b^3)/3)*a^3)/6 + ((-(16*D[22]*c[1]^2*b^4)/(3*a^8) + 24*D[22]*c[1]^2*b^3/a^7 - (288*D[22]*c[1]^2*b^2)/(7*a^6) + 32*D[22]*c[1]^2*b/a^5 - (48*D[22]*c[1]^2)/(5*a^4))*a^2)/4 + (2*D[22]*c[1]^2*b^5)/(9*a^7) - D[22]*c[1]^2*b^4/a^6 + (12*D[22]*c[1]^2*b^3)/(7*a^5) - (4*D[22]*c[1]^2*b^2)/(3*a^4) + (2*D[22]*c[1]^2*b)/(5*a^3)

This shows basically what is happening and why Maple gives answers you have. The are correct.

Download A_23-2-23-how_maple_gets_answer.mw