Question

Rearrange this equation to isolate c

a=b(1/c - 1/d)

Answer 1

Solution:
First, you need to apply the Distributive Property,
a = b(1/c) + b(-1/d)
a = b/c - b/d

Next, we can move b/d to the other side:
a + b/d = b/c - b/d + b/d
a + b/d = b/c

Next we need to cross multiply the expressions:
(a+b/d)(c) = b

Now, simply divide out the (a+b/d) from the left hand side:

c = b/(a + b/d)

Answer 2

I do not understand why you cross multiply and use c ?