Can anybody help me with these, they're awfully confusing.

20) a) 6.8 b) 7

21) a) 26.2 b) 26

22) a) -7.8 b) -8

23) a) -10.2 b) -10

24) a) 2.6 b) 3

25) a) -12.9 b) -13

9) Real number

10) Real number

11) Real number

12) Real number

13) Real number

14) Real number

15) Not a real number

16) Real number

Explanation

In order to find the estimated integer of a square root, you simply find the perfect squares closest to the specified square root. For example, the closest perfect squares to are and . Now, we need to find which perfect square is the closest between those two. 46 and 36 have a difference of 10, while 46 and 49 have a difference of 3. So, we know that 49 is the closest perfect square. Now, we simplify