任何数的平方不小于0,所以（x-1）²的值恒大于或等于零（1/2+5）²≥0,∴（1/2+5）²+1≥1,最小值是1 5x²-6x+11=5(x²-6/5x)+11=5(x-3/5)²-9/5+11=5(x-3/5)²+46/5≥46/5,值恒大于0,...