4 Show that the 5 questions on page 63 of this book can be answered without any special considerations.

Let be given the following equation in conjunctive form:
(x1 ∨ x3 ∨ x5 ∨ x6)(x3 ∨ x4 ∨ x5 ∨ x6)(x2 ∨ x4 ∨ x6)(x1 ∨ x3 ∨ x5) = 1.