1 若正数a ,b满足ab=a+b+3,则ab的取值范围是?2 已知x,y,z∈R+,且x-2y+3z=0,则y2/xz的最小值为?
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![1 若正数a ,b满足ab=a+b+3,则ab的取值范围是?2 已知x,y,z∈R+,且x-2y+3z=0,则y2/xz的最小值为?](/uploads/image/z/1329987-3-7.jpg?t=1%26%23160%3B%26%23160%3B+%E8%8B%A5%E6%AD%A3%E6%95%B0a+%2Cb%E6%BB%A1%E8%B6%B3ab%3Da%2Bb%2B3%2C%E5%88%99ab%E7%9A%84%E5%8F%96%E5%80%BC%E8%8C%83%E5%9B%B4%E6%98%AF%3F2%26%23160%3B%26%23160%3B+%E5%B7%B2%E7%9F%A5x%2Cy%2Cz%E2%88%88R%2B%2C%E4%B8%94x-2y%2B3z%3D0%2C%E5%88%99y2%2Fxz%E7%9A%84%E6%9C%80%E5%B0%8F%E5%80%BC%E4%B8%BA%3F)
1 若正数a ,b满足ab=a+b+3,则ab的取值范围是?2 已知x,y,z∈R+,且x-2y+3z=0,则y2/xz的最小值为?
1 若正数a ,b满足ab=a+b+3,则ab的取值范围是?
2 已知x,y,z∈R+,且x-2y+3z=0,则y2/xz的最小值为?
1 若正数a ,b满足ab=a+b+3,则ab的取值范围是?2 已知x,y,z∈R+,且x-2y+3z=0,则y2/xz的最小值为?
a>0,b>0 a+b>=2√ab 所以a+b+3>=2√ab+3 所以ab>=2√ab+3 ab-2√ab-3>=0 (√ab-3)(√ab+1)>=0 √ab=3 √ab=3 ab>=9 x-2y+3z=0 两边除y x/y-2+3z/y=0 x/y+3z/y=2 x/y+3z/y>=2√(3xz/y²) 所以2√(3xz/y²)