The answer is 11 because you do the smallest parenthesis. and work your way out.
1. 66.60
2. 48.00
3. 71.40
4. 2.95
5. 3.35
6. 2.50
7. 16.75
8. 6.66
9. 583.30
10. 13.00
11. 18.65
14. 26.98
Hope this could help
<span>X squared minus 12
x^2 - 12 =0
x^2 = 12
x = 3V3 (V = square root)
or
x = 3.464</span>