Answer
a. There exists a valid argument that has false conclusion.
b. There exists a real number that is neither positive, nor negative, and nor zero.
Work Step by Step
Negation of the statements of the form, "For all x, q", q being a statement, is "There exists x, ~q".
Negation of the statements of the form, "There exists x, ~q", q being a statement, is "For all x, q".
The negation for each of the given statements is:
a. There exists a valid argument that has false conclusion.
b. There exists a real number that is neither positive, nor negative, and nor zero.
