2个数学题、急、吐血跪求!
1.已知x:y:z=1/2:2/3:3/4,求(1)x/x+y-z(2)x-y/y-z
2.若a:b=1:根2,a:c=2:根6,计算根2a+b+根3c/根6a+根3b+c.
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