1、a的五次方+a+1
=(a^5-a^2)+(a^2+a+1)
=a^2(a^3-1)+(a^2+a+1)
=a^2(a-1)(a^2+a+1)+(a^2+a+1)
=(a^2+a+1)(a^2(a-1)+1)
=(a^2+a+1)(a^3-a^2+1)
2、X3次方—3倍X平方+4
=(x^3+x^2)-4(x^2-1)
=x^2(x+1)-4(x-1)(x+1)
=(x^2-4(x-1))(x+1)
=(x^2-4x+4)(x+1)
=(x-2)^2(x+1)