Answer:
B
Step-by-step explanation:
recall that any radical expression 
has real solutions only if A is not negative. (otherwise you will have imaginary solutions)
hence in this case we have
,
for real solutions, 8x must be ≥ 0,
since 8 is a positive number, x must be ≥ 0 (answer)
Answer:c
Step-by-step explanation:none of these are good answers as they can all exist in flat Euclidean space. The best answer is c because a great circle exists in spherical (non-flat) geometry . However it’s not really correct to say you could never describe a great circle in Euclidean space and whoever wrote this question (not you, the original author of the question) deserves to bite their tongue on their dinner tonight
