(5/3)=(x/y) If x-y=5

We'll use the proportion
rule:

a/b = c/d
<=> (a-b)/b = (x-y)/y

We'll
apply this rule to the first equation:

 (5/3)=(x/y)
<=>  (5-3)/3 = (x-y)/y (3)

But, from the
second equation, we have x-y=5.

We'll substitute the
difference x-y by 5, in (3).

 (5-3)/3 =
5/y

2/3 = 5/y

We'll cross
multiply:

2y = 15

We'll divide
by 2:

y = 15/2

y
= 7.5

Now, we'll substitute y by 7.5, into
the second equation:

x-y=5

x -
7.5 = 5

We'll add 7.5 both
sides:

x = 5 +
7.5

x =
12.5