Need some help on solving this question

Answer:
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Step-by-step explanation:
s = (a-lr) / (s-r) Multiply both sides of the equation by (5-r) to get:
s (5-r) = a - lr Now add lr to both sides
s(5-r) + lr = a Done. ....or you can simplify it a bit further to
5s - sr + lr = a