(根号x-y)[(根号x-y)-1]=56 求x-y

问题描述:

(根号x-y)[(根号x-y)-1]=56 求x-y

√﹙x-y﹚=a
a﹙a-1﹚=56
a²-a-56=0
﹙a-8﹚﹙a+7﹚=0
a=8 a=-7(舍去)
x-y=64