Design Algorithm Analysis question

Consider the class of satisfiable boolean formulas in conjunctive normal form in which each clause contains three literals, 3-SAT ={SAT is 3-CNF }. Is there a polynomial-time algorithm for deciding whether or not a boolean formula in 3-CNF is satisfiable? If your answer is yes, then describe and analyze your algorithm. If your answer is no, then show that 3-SAT NPC