There are some circumstances in which we can tell an audience what to do, some where we must sell them (or convince) them to do something, and then there are those times when we do not have the authority (or power) to either tell or sell and must ask them to help us think through, or solve, the issues to come up with a plan of action.
However, we can also do all three all the time. When telling, we are displaying authority and power, and that can be persuasive (it can sell), especially if we have drawn ideas from the audience before the meeting and you give them credit for helping you solve the problem.
When selling, we can display confidence and authority (confidence is telling), relate stories that appeal to the audience, refer to individuals in the room by name, and engage them in dialogue or Q&A, thus allowing them to help solve the problem.
Finally, when solving (or facilitating a group discussion) we have the chance to tell the audience what will happen and in what sequence; and we have the right to try to sell a preferred outcome.
Tell, Sell, Solve. It’s a cliché in communication, and a useful one to consider. But I suspect really good speakers and facilitators are doing all three all the time.