Given B / a = D / C = 7 / 5, then 2b-3d / 2a-3d =? Wrong, it is known that B / a = D / C = 7 / 5, then 2b-3d / 2a-3c =?

7 / 5, because a = 7 / 5b, C = 7 / 5D,
2b-3d/(7/10b)-(7/15d)

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