( (x - 5)(x + 5))^2 + ((x - 3)(x + 5))^2 = 0
(x + 5)( (x -5)^2 + (x - 3)^2) = 0
( x + 5)( x^2-10x +25+ x^2-6x+ 9) = 0
( x + 5)( 2x^2 -16x + 34) = 0
x + 5 = 0
x = - 5
2x^2 - 16x + 34 = 0
x^2 - 8x + 17 = 0
D = b^2 - 4ac = 64 - 68 = - 4 дискриминант отрицательный,значит,корней нет.
Ответ: x = - 5