先化简再求值 8x^2-(x-2)(3x+1)8x^2-(x-2)(3x+1)-2(x+1)(x-1)其中x=-2

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先化简再求值 8x^2-(x-2)(3x+1)8x^2-(x-2)(3x+1)-2(x+1)(x-1)其中x=-2
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先化简再求值 8x^2-(x-2)(3x+1)8x^2-(x-2)(3x+1)-2(x+1)(x-1)其中x=-2
先化简再求值 8x^2-(x-2)(3x+1)
8x^2-(x-2)(3x+1)-2(x+1)(x-1)其中x=-2

先化简再求值 8x^2-(x-2)(3x+1)8x^2-(x-2)(3x+1)-2(x+1)(x-1)其中x=-2
8x^2-(x-2)(3x+1)-2(x+1)(x-1)
= 8x^2-(3x^2 - 6x +x-2)-2(x^2-1)
=3x^2 +5x+4
x = -2
原式 = 3*4 -10 +4 = 6

8x^2-(x-2)(3x+1)-2(x+1)(x-1)=8x²-(3x²-5x-2)-(2x²-2)=3x²+5x+4
x=2,原式=12+10+4=26