∵ 互为相反数的和为0∴ (x-y)²+√(5x-3y-16)=0∵ (x-y)²≥0,√(5x-3y-16)≥0 ,两个非负数的和为0,这两个非负数都为0∴ x-y=0 且 5x-3y-16=0解这个方程组,得 x=y=8∴ √(x²+3y²)=√(8²+3×...