1.(-1/2x)^7/(-1/2x)=(1/2x)^6=1/(64x^6)2.a^m+2/a^m+1=［a^(m/2)+√2/a^(m/2)］^2+1-2√23.(-c^2)^2n=nc^44.(x+a)(x+b)=x^2+ax+bx+ab5.(3mn+1)(3mn-1)-8m^2n^2=9m^2n^2-8m^2n^2=m^2n^2