一直x눀-3x-2=0,那么代数式((x-1)대-x눀+1)⼀(x-1)

2025-01-02 04:07:33
推荐回答(2个)
回答1:


x²-3x=2
原式=[(x-1)³-(x²-1)]/(x-1)
=[(x-1)³-(x-1)(x+1)]/(x-1)
=(x-1)²-(x+1)
=x²-2x+1-x-1
=x²-3x
=2

回答2:

((x-1)³-x²+1)/(x-1)=(x-1)(x²-2x+1-x-1)/(x-1)=x²-3x
因为x²-3x-2=0,即x²-3x=2
带入得
((x-1)³-x²+1)/(x-1)=(x-1)(x²-2x+1-x-1)/(x-1)=x²-3x=2