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Question
If a : b = c : d; then show that (ax+ by) : b = (cx+ dy) : d
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Solution
`"a"/"b" = "c"/"d" => "ax"/"b" = "cx"/"d"`
Adding y to both sides
`=> "ax"/"b" + "y" = "cx"/"d" + "y"`
`=> ("ax + by")/"b" = ("cx + dy")/"d"`
⇒ (ax + by) : b = (ex + dy) : d
Proved.
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