It’s B because it’s a primary source because it comes from him
2√7 - √26 ≈ 5.29150262213... - 5.09901951359...
... ≈ 0.19248310854...
The result is an irrational number not described by any of your answer selections.
None of the statements is true.
When taking square roots, you can't take square roots of negative roots of negative numbers. So, what will work for the domain of u(x) is what makes u(x) zero or more. We can make an inequality for that.
u(x) ≥ 0.

9x + 27 ≥ 0 by squaring both sides
9x ≥ -27
x ≥ -3
So the domain of the function is when x ≥ -3 is true.
2.
you had nothing for 1. and I am not sure what you mean by 4.
This is a list of all answers