已知(10y-3x)/(3x-y)=2 且x>0 求 ((15-8y)^(1/2))/((5x+4y)^(1/2))
问题描述:
已知(10y-3x)/(3x-y)=2 且x>0 求 ((15-8y)^(1/2))/((5x+4y)^(1/2))
牛人速度来做
是15-8y 不是15x-8y
答
(10y-3x)/(3x-y)=2
10y-3x=6x-2y
9x=12y
y=3x/4
((15-8y)^(1/2))/((5x+4y)^(1/2))
=[(15-8y)/(5x+4y)]^(1/2)
=[(15-6x)/(8x)]^(1/2)
15-6x>=0
x