Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
(2, 5) 与 (6, 9) 的中点。（答： (4, 7) 。）
(2, 5) 与 (6, 9) 的中点。（答： (4, 7) 。）
Natural Language
Math Input
Extended Keyboard
