问题:
计算:
(1)a 2(a-1)+(a-5)(a+7);
(2)(x-5y) 2-(x+5y) 2;
(3)[(ab+1)(ab-1)-2a 2b 2+1]÷(-ab).
计算:
(1)a 2(a-1)+(a-5)(a+7);
(2)(x-5y) 2-(x+5y) 2;
(3)[(ab+1)(ab-1)-2a 2b 2+1]÷(-ab).
(1)a 2(a-1)+(a-5)(a+7);
(2)(x-5y) 2-(x+5y) 2;
(3)[(ab+1)(ab-1)-2a 2b 2+1]÷(-ab).
参考答案: