x=(根号3-根号2)/(根号3+根号2)=(根号3-根号2)^2/[(根号3)^2-(根号2)^2]=(根号3-根号2)^2=5-2*根号6类似可得 y=5+2*根号6xy=1, x^2+y^2=(5-2*根号6)^2+(5+2*根号6)^2=98故3X²—5XY+3Y²＝289根号3X²—5XY+3Y²＝17
