Question

若多项式x²-2x+3=A（x+1）²+B（x+1）+C其中ABC为常数，求A+B+C的值

要过程和答案。。注意过程啊

Answer 1

解由x²-2x+3
=x²+2x+1-2x-2x+3-1
=(x+1)²-2x-2x+3-1
=(x+1)²-4x+2
=(x+1)²-4x-8+8+2
=(x+1)²-4(x+2)+10
=A（x+1）²+B（x+1）+C
即A=1,B=-4,C=10
即A+B+C
=1+(-4)+10
=7