Answer:
It's a - (minus) sign.
Step-by-step explanation:
This is because √9 is 3, and therefore 6-3=3.
Hope I helped :)
Answer:

Explanation:

[ make the denominator same ]

[ apply fraction rule ]

[ simplify ]

What do you mean? Question not clear.
Each of A, C, and D are rational, so presumably B is the answer here.
A is rational, since

, so

.
C is also rational. If

, then

. This would mean

, and so

.
D is rational by a similar argument. If

, then

. So,

, which means

.