Question

(a) translate the argument into symbolic form and (b) determine if the argument is valid or invalid. You may compare the argument to a standard form or use a truth table.

If Nicholas Thompson teaches this course, then I will get a passing grade.
I did not get a passing grade.
∴ Nicholas Thompson did not teach the course.

Answer 1

Assume that p = Nicholas Thompson teaches this course. Assume q = I will get a passing grade. 
The symbolic form is ~q->~p

The truth table is:

p.       ~p        q.       ~q.       ~q->~p

T.        F        T.        F.               T
T.        F        F.        T.               F
F.        T        T.        F.               T
F.        T        F.        T.               T

So the conclusion is valid.

Answer 2

f t t f f