A³+a⁴

To simplify the expression a³ + a⁴, we notice that both terms have the same base, which is 'a'.

When adding terms with the same base, we can simply add their exponents.

Therefore, a³ + a⁴ can be simplified as a^(3+4), which is equal to a⁷.

So, the simplified form of a³ + a⁴ is a⁷.