Answer:
Voted for what exactly? I could help you more if you had a more definitive question. Unfortunately, I cannot answer this for you.
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.
The answer is C. 5x
We need to find the price of one magazine. To do this we divide 350 by 70
350 / 70 = $5 per magazine