Răspuns:
a) X^2 + 2X # 0 =>X#{0, -2)
(4 - X^2) = (2 - X)(2 + X) # 0 =>X#{2, -2}
=> X#{-2, 0, 2}
b) X(X+4) # 0 =>X#{-4, 0}
X(X-4) # 0 =>X#{0, 4}
=> X#{-4, 0, 4}
c) 9-X^2 # 0 =>X#{-3, 3}
d) X(X-5) # 0 =>X#{0, 5}
e) X^2 - 64 # 0 =>X#{-8, 8}
f) X^2 - 1 # 0 => X#{-1, 1}