# If a : B = C : D, Prove That: 5a + 7b : 5a – 7b = 5c + 7d : 5c – 7d. - Mathematics

Sum

If a : b = c : d, prove that: 5a + 7b : 5a – 7b = 5c + 7d : 5c – 7d.

#### Solution

Given a/b = c/d

=> (5a)/(7b) = (5c)/(7d)  (Multiplying each side by 5/7)

=> (5a + 7b)/(5a - 7b) = (5c + 7d)/(5c - 7d)  (By componendo and dividendo)

Concept: Componendo and Dividendo Properties
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#### APPEARS IN

Selina Concise Maths Class 10 ICSE
Chapter 7 Ratio and Proportion (Including Properties and Uses)
Exercise 7 (C) | Q 1.1 | Page 101