3m²-7m-4=o3(m^2-7/3m+(7/6)^2-(7/6)^2)-4=o3(m-7/6)^2-3*(49/36)-4=o3(m-7/6)^2=(49/12)+4(m-7/6)^2=97/36m=7/6+√97/6或m=7/6-√97/6x²+2(根号2-1)x+3-2根号2=0x²+2(√2-1)x+（√2-1)^2=0(x+√2-1)...m^是什么意思？m^2是m的平方