1.(a+2b)(a-2b)-(a+b)^2 原式=a²-4b²-a²-2ab-b² =-5b²-2ab 2.(x-½)^2-(x-i)(x-2) 原式=x²-1/4x+1/4-x²+2x+ix-2i =2又1/4+ix-2i
2012-03-31