G.K. LeChat

I have a question about problem number 54 on the 1999 AP exam.
The question states:
2NO(g) + O2(g) <=> 2NO2(g) delta H < 0 Which of the following changes alone would cause a decrease in the value of Keq for the reaction represented above?
a) decreasing the temperature
b) increasing the temperature
c) decreasing the volume of the reaction vessel
d) increasing the volume of the reaction vessel
e) adding a catalyst
The answer is (b). We call K the equilibrium constant for a reason. Changes in concentration or pressure will not change the value of K. Only temperature changes will cause K to change. You can look at K as the ratio of the forward and reverse rate constants. As temperature changes, the rates will change and the rate constants will change, giving a new value of K.
SHOW THEM, mathematically, how a SHIFT doesn't necessarily change K !