please explain..(R.S.agarwal question)

please explain the step marked in violet...

how????

[2] [2]

2 Answers

its all ratio-proportion property

m/2 = n/3
5m/10 = 3n/9 = 5m-3n/10-9

if a/b = c/d then they r also equal to a-b/c-d

a/b = c/d = a-c/b-d = a+c/b+d

thanks

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