(8分)化简并求值.15a2-[-4a2+2(3a-a2)-3a],其中a=-2
计算:
(本题6分)计算:
(每小题4分,共8分)(1)计算:×﹣4××(1﹣)0; 计算: (-)÷
计算:(每小题5分,共10分) (1)(2),
计算: (1) (2)