Set A is the set containing zero.
Set A is the empty set.
Both sets A and B are the empty set.
3) x^2=36
A. 9sqrt. 2 - 9sqrt. 2
B. 6 - 6
C. 4sqrt. 3 - 4sqrt. 3
D. 18 - 18
4) x^2=90
A. 10 sqrt. 3 - 10 sqrt. 3
B. 3 sqrt. 10 -3 sqrt. 10
C. 3 sqrt. 15- 3 sqrt. 15
D. 45 - 45