8x+4x(x-8)=3704x^2+24x-370=0x^2+6x-92.5=0当b^2-4ac>=0时 为x=[-b±(b^2-4ac)^(1/2)]/2a; x1={-6+[6*6-4*6(-92.5)]^1/2}/2=20.7x2={-6-[6*6-4*6(-92.5)]^1/2}/2=-26.7