（x+y-10)²+√(xy-6)=0∴{x+y-10=0xy-6=0即{x+y=10xy=6x³y-2x²y²+xy³=xy(x²-2xy+y²)=xy(x²+2xy+y²-4xy)=xy[(x+y)²-4xy]=6×(10²-4×6)=456