Contact us
Choose a category below so we can get back to you as quickly as possible.
(a+b)(c+d)-(ac+bd) =ad+bc-2abcd =(ad-bc)≥0 得證 麻煩採納,謝謝!
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.