X^2-根号2003x-520=0 设两个为x1,x2 所以x1+x2=根号2003,x1x2=-520 所以A^2=(|x1|+|x2|)^2 =x1^2+2|x1x2|+x2^2 =(x1+x2)^2-2x1x2+2|x1x2| =2003+4*520 =4083