Answer:
The expression √x+5+√1-x is defined for all values of x such that the value under the square root sign is non-negative. We can find the values of x that satisfy this condition by considering each of the square roots separately.
For the first square root, the value under the square root must be non-negative, so we have the following inequality:
x + 5 ≥ 0
x ≥ -5
For the second square root, the value under the square root must be non-negative, so we have the following inequality:
1 - x ≥ 0
x ≤ 1
Therefore, the expression is defined for all values of x that satisfy both of these inequalities. This means that the expression is defined for values of x in the range -5 ≤ x ≤ 1. The correct answer is therefore option D.