x1,x2是关于x的方程x²-2mx+m²-4=0的两个实数根,
x1²-2mx1+m²-4=0,
x1+x2=2m;
x1²+2mx1+4mx2=3m²+8,
即(x1²-2mx1+m²-4)+4mx1+4mx2=4m²+4,
即 0+4m(x1+x2)=4m²+4,
即 4m*(2m)=4m²+4
即 m²=1,m=±1
x1,x2是关于x的方程x²-2mx+m²-4=0的两个实数根,
x1²-2mx1+m²-4=0,
x1+x2=2m;
x1²+2mx1+4mx2=3m²+8,
即(x1²-2mx1+m²-4)+4mx1+4mx2=4m²+4,
即 0+4m(x1+x2)=4m²+4,
即 4m*(2m)=4m²+4
即 m²=1,m=±1