化简求值 已知x^2-2x=-1⼀3,将(x-1)^2+(x+3)(x-3)+(x-3)(x-1)

2024-11-27 09:58:41
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回答1:

∵x²-2x=-1/3
x²-2x+1=-1/3+1
∴(x-1)²=2/3
(x-1)^2+(x+3)(x-3)+(x-3)(x-1)
=(x-1)²+x²-9+x²-4x+3
=(x-1)²+2x²-4x+2-8
=(x-1)²+2(x-1)²-8
=3(x-1)²-8
=3×(2/3)²-8
=4/3-8
=-20/3