Explanation:
one number = x
second number = y
x = y - 5
2y = 5x - 2
we simply have 2 equations with 2 variables.
to solve we use the first identity and use it in the second equation :
2y = 5(y - 5) - 2 = 5y - 25 - 2 = 5y - 27
27 = 3y
y = 27/3 = 9
x = y - 5 = 9 - 5 = 4
the numbers are 4 and 9.