3x(1-2x)=3x-6x²=-6(x²-0.5x)=-6(x²-0.5x+1/16-1/16)=-6(x-1/4)²+3/8∵(x-1/4)²≥0∴-6(x-1/4)²≤0∴-6(x-1/4)²最大值为0∴y=3x(1-2x)最大值为3/8lz你算的是对的,只不过符号弄错...