？じゃなくて
がいしゅつ

https://www.research.ibm.com/haifa/ponderthis/download/Feb2004_dima.pdf

(-snip-)
(1)　p(p + q) = 2r^2d
(2)　p(p + q)q(p ? q) = 2rs(r^2 ? s^2)d^2
(-snip-)
uv [u ( 24u^3 - 34u^2v + 24uv^2 - 17v^3 ) + 6v^4 ] = 0,
so u| 6v^4 ⇒ u| 6, u even ⇒ u = 2, v = 3 .
The ONLY solution in this case is:
p = 16, q = 11, r = 6, s = 5 (so d = 6):
lengths of the sides of ABC - primitive right triangle: (352, 135, 377),
lengths of the sides of DEG - right triangle: (360, 66, 366),
lengths of the sides of DEF - isosceles triangle: DE=DF=366, EF=132,
indeed P_ABC = P_DEF = 864, = S_ABC = S_DEF = 23760 .
The system (A) has this UNIQUE solution.

わかった？