我们知道，一个正数的正的平方根叫做这个数的算术平方根，零的算术平方根是零．运用这一定义解题，有时显得十分简捷明快．现举例说明之．平方根．分析由算术根定义及绝对值定义知＋８＝０，解得ｘ＝－２，ｙ＝４．故ｘｙ＝（－２）４＝１６，其平方根为±４．例２若ｘ、ｙ为 We know that the positive square root of a positive number is called the arithmetic square root of this number, and the square root of the arithmetic zero is zero. Using this definition to solve problems, sometimes seem very simple and neat. Here is an example. Square root. The analysis is defined by the definition of the arithmetic root and the definition of the absolute value is +8=0, and the solution is x=-2, y=4. So xy=(-2)4=16, its square root is ±4. Example 2 if x, y are