已知 | m |= 15,| n | = 27 且 | m + n |= m + n 则 m-n的值等于多少_数学解答

已知 | m |= 15,| n | = 27 且 | m + n |= m + n 则 m-n的值等于多少

人气：488 ℃　时间：2020-05-24 11:27:18

解答

| m |= 15, | n | = 27 则m=15或-15,n=27或-27
而 | m + n |= m + n 所以m=15,n=27
则 m-n=15-25=-12