Consider the following premises. For all x_7, x_7 will climb a mountain if and only if x_7 is a poet. For all x_7, if x_7 were a mechanic, then x_7 is climbing a mountain. For all x_7, x_7 is not a poet. Can we infer the following from them? There is at least one x_7 for which x_7 is a mechanic.
 From the fact that for all x_7, x_7 will climb a mountain if and only if x_7 is a poet we can infer that for all x_7, if x_7 climbs a mountain, then x_7 is a poet. From the fact that for all x_7, if x_7 were a mechanic, then x_7 is climbing a mountain, and that for all x_7, if x_7 climbs a mountain, then x_7 is a poet we can infer that for all x_7, if x_7 were a mechanic, then x_7 is a poet. Finally, from the fact that for all x_7, if x_7 were a mechanic, then x_7 is a poet, and that for all x_7, x_7 is not a poet we can infer that for all x_7, x_7 is not a mechanic, which contradicts that There is at least one x_7 for which x_7 is a mechanic. Therefore, the answer is no.