Consider the following premises. For all x_7, if x_7 takes a plane, then x_7 is poor. For all x_7, x_7 will climb a mountain. For all x_7, x_7 is happy or x_7 will take a plane. For all x_7, if x_7 were happy, then x_7 is poor. Can we infer the following from them? If we can, name the inference rule being used: Barbara is not climbing a mountain.
That contradicts the premises. Therefore the answer is no.