x^2-2x-2=0
(x-1)^2-1-2=0
(x-1)^2=3
x-1=根号3 x=1+根号3
x-1=-根号3 x=1-根号3
3x^2+2x-9=0
x^2+2x/3-3=0
(x+1/3)^2-3-1/9=0
(x+1/3)^2=28/9=4*7/9
x+1/3=(2/3)*根号7 x=(2/3)*根号7-1/3=(-1+2根号7)/3
x+1/3=-(2/3)*根号7 x=-(2/3)*根号7-1/3=(-1-2根号7)/3
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