1b) The first step is to translate the argument into symbolic form. To form an argument we need a collection of premises and a conclusion. The conclusion is normally the statement which begins with "Therefore", "Hence" or "Thus". In this case, there are two premises. The first premise is "If Bill is a cheater, then Bill sits in the back row." The second premise is "Bill sits in the back row." The conclusion is "Therefore Bill is a cheater."
Let c represent "Bill is a cheater", and let s represent "Bill sits in the back row." Now write each of the premises and the conclusion in symbolic form.