Find all possible values $a,b\in [0,10^9]$ such that $a+b=ab$

Question

My problem:

Find all possible values of a and b such that $a+b=ab$, given that values of $a$ and $b$ are contained in the interval $[0,10^9]$

Answer 1

Hint: $a + b = ab$ is the same as $(a-1)(b-1) = 1$.