化简再求值:(x+2)(x-2)+(x-2)²+(x-4)(x-1)其中x²-3x=2

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化简再求值:(x+2)(x-2)+(x-2)²+(x-4)(x-1)其中x²-3x=2
化简再求值:(x+2)(x-2)+(x-2)²+(x-4)(x-1)其中x²-3x=2

化简再求值:(x+2)(x-2)+(x-2)²+(x-4)(x-1)其中x²-3x=2
原式=x²-4+x²-4x+4+x²-5x+4
=3x²-9x+4
=3(x²-3x)+4
=3×2+4
=10

= x^2-4+x^2-4x+4+x^2-5x+4
= 3x^2 - 9x + 4
=3 (x^2-3x) +4
=3*2+4
=10

(x+2)(x-2)+(x-2)²+(x-4)(x-1)
=x^2-4+x^2-4x+4+x^2-5x+4
=3x^2-9x+4
=3(x^2-3)+4
因:x²-3x=2
所以原式=10