Alright kiddo, so you know how sometimes people have to solve problems and figure out what variables will make the problem true? Well, sometimes there are different ways to write the same problem and they might use different variables or symbols. Equisatisfiability is when two different ways of writing a problem will have the same number of solutions, or in other words, it means they are equally solvable.
Let's try to make it simpler. Imagine there are two people, Alex and Bob, and they have each written a different math problem on a piece of paper. Even though they wrote different problems, they might still have the same answer. Equisatisfiability is like saying that both problems are equally solvable or have the same number of solutions.
This concept is important because it helps mathematicians and computer scientists know when they can simplify a problem or use different notation without changing the answer. It also helps them figure out which problems are harder to solve than others. So, basically, equisatisfiability means that different ways of writing a problem can have the same answer, which is really useful when trying to solve problems.