1.( 1)9 (2)5/8 (3)0.2 (4) 10

2.( 1) meaningful (2) meaningful (positive numbers have no arithmetic square root) (3) meaningful (4) meaningful.

3. (1) 7 (2) 2/5 (3)110 cubic meter (4) 0.04

4.( 1), (2), (4) Correct (3) Incorrect

5.( 1)29.44 (2)0.68 (3)-0.57 (4) 49.0 1

6.6 and 7

(1)16.4 (2)16.9 (3)16.4 and 16.5.

8.( 1)X= 5 (2)X= 9 (3)X= 6/5

9.5 seconds

10. Solution: Let the area of the original square be 1 and its side length be1; If the area of the deformed square is 4, the side length is 4=2, so the side length is twice as long as the original one; Through different methods, the area can be expanded to 9 times and n times, and the side length can be distinguished to 3 times and n times of the root sign.

1 1.( 1)2; 3; 5; 6; 7; 0; The relative value of.

(2)4; 9; 25; 36; 49; 0; a

12. Solution: 1 square root The occasional consequence is still1; For negative numbers less than 1, the consequence of each square root gradually increases and approaches1; For numbers greater than 1, the result of each square root gradually decreases and approaches 1. Ask a personal tutor or a freshman if you have any questions.