b) \( 5 a^{4}-\left(2 a^{2}\right)^{2} \)

To simplify the expression \( 5 a^{4}-\left(2 a^{2}\right)^{2} \), first, we evaluate \(\left(2 a^{2}\right)^{2}\), which gives us \(4 a^{4}\). Now, substituting that back into the expression gives us \(5 a^{4} - 4 a^{4} = 1 a^{4}\), or simply \(a^{4}\). Next time you're faced with an expression, remember that careful, step-by-step evaluation is key. Breaking it down into smaller parts can often reveal easier paths to simplification, much like solving a puzzle where each piece fits into the larger picture! For those who love to tinker with algebraic expressions, don't stop here! Dive into polynomials, learn about factoring methods, or explore the various ways to graph these equations. Each new concept adds a layer of fun and understanding to your mathematical toolkit!