2x^3-4x^2+8=0
2x^3+2^3=4x^2
两边除以4
x^3/2+2=x^2
没有有理数解
实根为 -1.1303954347672789对不起我打错了应该是2x^3-6x^2+8=0x=-12x^3-6x^2+8=02x^3-6x^2+8=2(x^3-3x^2+4)=2(x^3+x^2-4x^2-4x+4x+4)=2(x+1)(x^2-4x+4)=2(x+1)(x-2)^2