Here's my homework, teacher: Article 1, section 8: Congress may lay and collect taxes for the "common defense" or "general welfare" of the United States.
This does not equate to a power to spend tax money on (or regulate) anything "for the 'common defense' or 'general welfare'". If Congress's enumerated powers included getting involved in education, this clause would grant them the power to raise money toward that end. It does not grant that power by itself. If it did, the remainder of the section (and the entire concept of enumerated powers) would be rendered meaningless, which was obviously not the authors' or signers' intent.
Don't worry, this is a very common mistake. Your reading comprehension will improve with practice. In the meantime, perhaps you would care to read what Thomas Jefferson and James Madison had to say on the subject.