1: solution (1)? 49=7; (2) ? (25/ 196)=5/ 14; (3) ? 0.09=0.3; (4)-? 64=-8.

2. Solution: Because 1 1? = 12 1, so the arithmetic square root of 12 1 is1,that is? 12 1= 1 1; Because (3/5)? =9/25, so the arithmetic square root of 9/25 is 3/5, that is? (9/25)=3/5; Because 1.4? = 1.96, so the arithmetic square root of 1.96 is 3/5, that is? (9/25)=3/5; 1.4? = 1.96, then the arithmetic square root of 1.96 is 1.4, that is? 1.96= 1.4; Because (10? )? = 10 6, so? (〖 10〗^6 )= 10? .

3. solution: let the side length of the square be x and the area be a, and get x from the square area formula. = A. When the area of a square becomes four times the original, then 4a=4x? =(2x)？ So its side length has doubled. Similarly, when the area becomes 9 times of the original, its side length becomes 3 times of the original; When the area becomes 100 times, its side length becomes 10 times; When the area is n times the original, its side length becomes the original? N times.

Beijing Normal University Edition Eighth Grade Mathematics Textbook Volume 1 Answer (2) Exercise 2.5

Answers to the eighth grade mathematics textbook published by Beijing Normal University (3)