x1^2-x2^2=0(x1+x2)(x1-x2)=0解得x1=-x2或x1=x2判别式=（2m-1）^2-4m^2=1-4m当判别式=0时，x1=x2即1-4m=0得m=1/4当判别式>0时，x1=[-(2m-1)+√(1-4m)]/2x2=[-(2m-1)-√(1-4m)]/2由x1=-x2得[-(2m-1)+√(1-4m)]/2=[(2m-1)+√(1-4m)]/2解得m=1/4
