Решение 

 

 

 

 

 

x = 2 

Проверка 

> restart; -1; with(RealDomain); -1; solve(`+`(RealDomain:-`^`(`+`(x, `-`(3)), 6), RealDomain:-`^`(`+`(RealDomain:-`^`(x, 2), `-`(`*`(2, `*`(x))), `-`(1)), 3)) = 0)
 

2 (64.2.1)