解:a2-3=a2(4-a)-a a2-3=4a2-a3-aa3-3a2+a-3=0 ∵(a-1)3=a3-3a2-3a+1∴原方程变为:a3-3a2-3a+1+4a-4=0(a-1)3+4(a-1)=0设a-1=x,则:x3+4x=0,x(x2+4)=0,∵x2+4≥4,∴x=0,即:a-1=0,a=1.
a2-3=a2(4-a)-aa-3=a2(3-a)(a2+1)(3-a)=03-a=0a=3