On the growth rate If the number of fixed line telephones was 10 million in 2000 and 70 million in 2008, what is the increase rate? 7000 divided by 1000-1 = 70%? If it is a year, there will be 8 years from 2000 to 2008

On the growth rate If the number of fixed line telephones was 10 million in 2000 and 70 million in 2008, what is the increase rate? 7000 divided by 1000-1 = 70%? If it is a year, there will be 8 years from 2000 to 2008

1000（1+n）^8=7000
(1+n)^8=7
8lg(1+n)=lg7
lg(1+n)=(lg7)/8=0.1056
1+n=1.275
n=0.275=27.5%
The average annual growth rate is 27.5%

On absolute value in mathematics of grade one
|X-2 | + | y + 3 | + | Z-5 | = 0. Find the value of | x | + | y | + | Z |

Because | X-2 | + | y + 3 | + | Z-5 | = 0, and equal to zero, there are two cases, one is the sum of opposite numbers, the other is that it is zero, and the value range of each absolute value in the question is greater than or equal to 0, so the value of each absolute value in the question is 0, so X-2 = 0, y + 3 = 0, Z-5 = 0, that is, x = 2, y = - 3, z = 5, so | x | + | y | +

On absolute value
1. Given A-1 + B-2 = 0, find the value of 3A + 2B
2. If x = 5, y = 3 and x > y, find the value of X + y

(1) Because only when the two addends are 0, the sum is 0, that is, 0 + 0 = 0, so A-1 = 0, B-2 = 0, the solution is a = 1, B = 2; so 3A + 2B = 3 + 2 * 2 = 7 (2), x = 5, y = 3, we can get x = ± 5, y = ± 3, x = 5, y = ± 3x + y = 5 ± 3, x + y =..., because x ＞ y, so x = 5, y = ± 3x + y = 5 ± 3