Since base is common,apply the product of powers property: a^m·aⁿ= a^{m + n}.

4² · 4⁹ = 4^{2 + 9}

= 4¹¹                            (Add  exponents: 2 + 9 = 11)

The product of  4² · 4⁹ is 4¹¹.