(a^2+7a+10)/(a^2-a+1)*(a^4+a)/(a^2+4a+3)/(a^2+a)/(a+2)当a=-1时,化简求值

a-2a+3a-4a+5a-6a+7a-8a+9a-10a+11a.+99a-100a= (a 1)(a 2)(a 3)(a (a+2)(a+1)-a(a-3) 合并同类项：a-2a-3a+4a+5a-6a-7a+8a+9a-10a-11a+12a+……+2008a+2009a-2010a-2011a a-1/a+2 1-a/-2-a -2×a×1/a 计算;(a^3)^4+a^10×a^2-a×a^2-a*a^3*a^8 分式计算(a+1/a^2+3a+2)+(a+3/a^2+7a+12) 化简1/a(a+10）+1/（a+1)(a+2)+...+1/(a+2009)(a+2010) 化简(a+ 3)(a-3) (a-5)(a+7)-2a(a-1) (a+3)(a-3)+(a-5)(a+7)-2a(a-1)怎么做? a>0,求a+a^3+a^5+a^7+.a^2n-1 计算：[a-(1/a)]/a^2-2a+1/a (a^2+7a+10)/(a^2-a+1)*(a^4+a)/(a^2+4a+3)/(a^2+a)/(a+2)当a=-1时,化简求值 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=[ ] a-2a-3a+4a+5a-6a-7a+8a+9a-10a-11a.+2008a+2009a-2010a-2011a如何合并同类项?