（1）2x²-√ 2x-1=0x²-√2x/2=1/2(x-√2/4)²=1/2+1/8(x-√2/4)²=5/8x-√2/4=±√10/4x=(√2±√10)/42）2/3x²-1/6x-1/2=0两边同乘以6得：4x²-x-3=0(4x+3)(x-1)=0x=-3/4或x=1...