Exercise 1.12.5: Proving arguments in English are valid or invalid.

Give the form of each argument. Then prove whether the argument is valid or invalid. For valid arguments, use the rules of inference to prove validity

(c) I will buy a new car and a new house only if I get a job. I am not going to get a job. I will not buy a new car.

(d) I will buy a new car and a new house only if I get a job. I am not going to get a job. I will buy a new house. I will not buy a new car.