Is 2 over 5 the equivalent of 18 over 45?

Oh, dude, let me break it down for you. So, if you simplify 2/5, you get 2/5. And if you simplify 18/45, you also get 2/5. So yeah, they're equivalent. It's like asking if a hot dog is the same as a wiener in a bun - different names, same thing.