已知x,y满足√4x-5y+√x-y-1=0,则√xy-√x/y的值为多少?我算出了x=5,y=4,但后面不知怎么算
问题描述：
已知x,y满足√4x-5y+√x-y-1=0,则√xy-√x/y的值为多少?我算出了x=5,y=4,但后面不知怎么算
答
原式=√(5×4)-√(5/4)
=√(5×2²)-√(5/2²)
=2√5-√5/2
=(2-1/2)√5
=3(√5)/2怎么算的2√5-√5/2=(2-1/2)√5=3(√5)/2系数是2和-1/2