You have the next expression:
![9+\sqrt[]{81}-4\cdot2](https://img.qammunity.org/2023/formulas/mathematics/college/rje6oef5rvjyof4j16cc4fedmbwra12m1w.png)
The order of operations is:
1. Multiplications and divisions (left to right)
2. Addition and substraction (left to right)
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As you have a square root this is the first operation:
As 81 is a perfect square you know that:
![\sqrt[]{81}=9](https://img.qammunity.org/2023/formulas/mathematics/college/hrgr76taiv5j1qtpaini7j6mfty2s9db8b.png)

Then, You make the multiply of (4*2)

And finally you make the additions and substractions:
