Just first question

4 Semantic Tableaux 1. For each of the following formulas, construct a semantic tableau as described in the class notes to check the satisfiability of the formula. Explicitly write if the formula is satisfiable or not according to the tableau. (a) (a + ab) = (a + b) (b) (pVg) (p) AqA 2. For each of the following formulas, construct a semantie tableau to check the validity of the formula. Explicitly write if the formula is valid or not according to the tableau. (a) (p1q+r) (p --+r)^(q + r)) (b) (a -b) + ((a vb)(a V-b))