4x²-6x-3=0 4x²-6x=3 方程两边同时除以4x²-(3/2)x=3/4x²-(3/2)x+(3/4)²=3/4+(3/4)²(x-3/4)²=21/16x-3/4=±√(21/16)x-3/4=±√21/4x=(3±√21)/4x1=(3+√21)/4x2=(3-√21)/4...