题目

按要求解方程：1.2.3.(公式法)4.（配方法）  答案： 1.解： ………………………………………3分      ∴或       ∴……………………………………5分2.解：………………………………………3分      ∴或       ∴……………………………………5分3.解：∵                    ………………………………………1分    ∴>0，… I regret _____ you that the goods you delivered to us are not the ones we ordered. I would appreciate _______ if you solve the problem as soon as possible. A. informing; it 　　　　　　 B. having informed; / C. to inform; it 　　　　　　 D. to inform; that