题目

先化简，再求值： ， 其中 ． 答案：解：原式＝（x2y﹣3x2y）+（xy﹣xy）＝﹣2x2y∵x＝﹣2，y=12∴原式＝﹣2×（﹣2）2 ×12 ＝﹣2×4×12＝﹣4-Hello, May I speak to Daniel?-__________.A.Sorry, he’s not at home. Who’re you?B.Sorry, he’s not at home. Who’s that speaking, please?C.Sorry, you can’t.D.Sorry, you mustn’t.