Answer:
Options C and F
Explanation:
Check each answer:
6^2=36 but 36<64 so it cannot be A
8^2=64 but 64<64 (remember that even though they are equal to each other it doesn't meet the requirements of the inequality) so it cannot be B
11^2=121 and 121>64 so it can be C
-6^2=36 but 36<64 so it cannot be D (remember that squaring a number that is negative results in a positive number)
-8^2=64 but 64<64 so it cannot be E (see explanations for B and D)
-11^2=121 and 121>64 so it can be F
Therefore, the only two correct solutions are options C and F