ax^2-2x+3=(x+3)(ax+b)=ax^2+bx+3ax+3b
-2=(b+3a)
3=3b
b=1,a=-1
所以ax^2-2x+3=-x^2-2x+3,
=(1-x)(x+3),x=1或x=-3
另一个因式为1-x