(4√3+√27)√3

To simplify the expression \( (4\sqrt{3} + \sqrt{27})\sqrt{3} \), follow these steps:

1. First, simplify \( \sqrt{27} \): \[ \sqrt{27} = \sqrt{9 \times 3} = \sqrt{9} \times \sqrt{3} = 3\sqrt{3}. \]

2. Substitute \( \sqrt{27} \) into the expression: \[ (4\sqrt{3} + 3\sqrt{3})\sqrt{3}. \]

3. Combine the terms inside the parentheses: \[ 4\sqrt{3} + 3\sqrt{3} = (4 + 3)\sqrt{3} = 7\sqrt{3}. \]

4. Now multiply by \( \sqrt{3} \): \[ 7\sqrt{3} \cdot \sqrt{3} = 7 \times 3 = 21. \]

Therefore, the simplified result is: \[ \boxed{21}. \]