2x1240用适当方法解(2x-1)2-4=0(2x-1)2=22│2x-1│=22x-1=±2x=3/2或x=-1/2移项，开方2，2t27t40解一元二次方程用配方法解答别的方法不要2t2-7t-4=0t2-7t/2-2=0(t-7/4)2-49/16-2=0（t-7/4）2=81/16t-7/4=±9/4t=4或t=-1/22t^2-7t-4=0（2t+1)(t-4)=0t1=-1/2,t2=4(2t+1)(t-4)=0t=-1/2或43，X32X27X40的因式分解详细过程无需答案谢谢-x3+