Answer: 729
Step-by-step explanation: what we are seeing here is known as exponents, how exponents work is that you have to multiply a number a certain times, depending on the power of #.
3^2 = 9 because simplified, its 3 * 3
3^4 = 81 because simplified, its 3 * 3 * 3 * 3
now the solution would be 9 * 81, which equals 729
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hope this helps