Vreal numbers r, a, and b, if r is positive, then () = ,ab r = 3, a = 1/2, and h = 6 are particular real numbers such that r is positive. 4. Use universal modus tollens to fill in valid conclusions for the arguments in 5 and 6. All irrational numbers are real numbers. o is not a real number. 5. 19. Rewrite the statement "No good cars are cheap" in the form "Vx, if P(x) then ~Q(x)." Indicate whether each of the following arguments is valid or invalid, and justify your answers. No good car is cheap. A Rimbaud is a good car. .. A Rimbaud is not cheap. No good car is cheap. A Simbaru is not cheap. .. A Simbaru is a good car. No good car is cheap. A VX Roadster is cheap. .. A VX Roadster is not good. No good car is cheap. An Omnex is not a good car. .. An Omnex is cheap. . b. . d.