已知:x=根号2-1分之3,求x+2分之x^2-x-6

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已知:x=根号2-1分之3,求x+2分之x^2-x-6

已知:x=根号2-1分之3,求x+2分之x^2-x-6
已知:x=根号2-1分之3,求x+2分之x^2-x-6

已知:x=根号2-1分之3,求x+2分之x^2-x-6
已知:x=根号2-1分之3
x=3(√2+1)/(√2-1)(√2+1)
x=3√2+3
x+2分之x^2-x-6
=(x-3)(x+2)/(x-2)
=(3√2+3-3)(3√2+3+2)/(3√2+3-2)
=(3√2)(3√2+5)/(3√2+1)
=(3√2)(3√2+5)(3√2-1)/(3√2+1)(3√2-1)
=(18+15√2)(3√2-1)/(18-1)
=(54√2-18+90-15√2)/(18-1)
=(39√2+72)/17


x=(根号2-1)分之3
x=3(√2+1)/(√2-1)(√2+1)
x=3√2+3
(x+2)分之(x^2-x-6)
=(x-3)(x+2)/(x+2)
=(x-3)
=3√2