This is the concept of quadratic equations. We are required to find the missing factor in the partially factored quadratic equation given;
n(n-3)+2(n-3)=()(n-3)
here we proceed as follows;
n(n-3)+2(n-3)
when we factor this we get:
(n-3)(n+2)
this can be written as:
(n+2)(n-3)
The answer is (n+2)