19、20拜托了

发布网友发布时间：2022-04-30 10:08

共2个回答

热心网友时间：2022-06-20 22:42

Changshan, China(Jilin) Forecast
Friday, Aug 18
Partly sunny and pleasant High: 25° C Low: 12° C
Saturday, Aug 19
Sunny High: 27° C Low: 13° C
Sunday, Aug 20
Rain High: 23° C Low: 11° C
Monday, Aug 21
Rain High: 22° C Low: 11° C
Tuesday, Aug 22
Morning rain; mainly cloudy High: 21° C Low: 13° C
Wednesday, Aug 23
Partly sunny High: 23° C Low: 14° C
Thursday, Aug 24
Mostly sunny High: 25° C Low: 14° C
Friday, Aug 25
Several hours of sunshine High: 23° C Low: 11° C
Saturday, Aug 26

热心网友时间：2022-06-20 22:43

19题如下
（1）（m-n）^2
(m+n)^2-4mn
(2) (m+n)^2-(m-n)^2=4mn
(3) a+b=8

20题如下
（3+1)（3^2+1）(3^4+1)(3^8+1).....(3^64+1)
=1/2(3+1)(3-1)（3^2+1）(3^4+1)(3^8+1).....(3^64+1)
=1/2(3^2-1)（3^2+1）(3^4+1)(3^8+1).....(3^64+1)
=1/2(3^64-1)(3^64+1)
1/2(3^128-1)