1/50,3/100,1/25,()A,1/10B,1/16C,1/20D,1/15

化简多项式a-2a+3a-4a+5a-...+99a-100a用下面方法解决 a-(a+b)+(a+2b)-(a+3b)+...-(a+101b)解法1：a-2a+3a-4a+5a-..+99a-100a =(a+3a+5a+..+99a)+(-2a-4a-6a-...-100a)=2500a-2550a=-50a解法2：a-2a+3a-4a+5a-...+99a-100a=(a-2a)+(3a-4a)+(5a-6a)+.. 数学八年级下册轻巧夺冠50页第25题1/(a-1)+1/(a-1)(a-2)+1/(a-2)(a-3)+1/(a-3)(a-4)+...+1/(a-99)(a-100) a=-1 求a-2a+3a-4a+5a-6a+...+99a-100a 当a=1时,a-2a+3a-4a+AA+99a-100a的值是A:5050 B:100 C:50 D:-50 当a=1时,a-2a+3a-4a+5a…+99a-100a= (a 1)(a 2)(a 3)(a (a+2)(a+1)-a(a-3) 1/(a-1)+1/(a-1)(a-2)+1(a-2)(a-3).1/(a-99)(a-100) 当a=1时,求a-2a+3a-4a+...+99a-100a的值 A-A=0 A+A=?A÷A=1 A×A=?(A+A)+(A-A)+(AxA+A÷A）=100 A=? 怎么计算(a+1)(a*a+1)a*a*a*a+1).a(100)+1) (a-1)(a-3) a(a-1)(a-2)(a-3)(a-4)因式分解 【1】a+a=a×a a= [ ]【2】a×a=a÷a a=[ ]【3】a×a=a－a a=[ ] [4]a－a=a＋a a=[ ] (通分） a/a^a^a+3a+2 ,a/a^a+2a+1 ,-1/3a+6 （a-a/a+1)/(a*a-2a)*(a+1)/(a*a+3a+2)要详细的计算说明！ a+a+1+a+2+a+3+a+4+a+5+a+6+a+7.+a+2013+a+2014=? 当a等于1时a-2a+3a-4a+……+99a-100a的值为A、5050 B、100 C、50 D、-50