5a^2•a

To simplify the expression \( 5a^2 \cdot a \), you can use the property of exponents that states when you multiply two expressions with the same base, you add the exponents.

So, you can rewrite the expression as:

\[ 5a^2 \cdot a = 5a^{2+1} = 5a^3 \]

Thus, the simplified expression is \( 5a^3 \).