There are infinitely many such numbers. they belong to the set n*15 where n is any integer.
15
1 and 15, and 3 and 5.
15*5
15 and 1 smarts
The two numbers you are looking for are -15 and 4. When you multiply -15 and 4, you get -60, and when you add them together, you get -13.
16 and 15
3 x 5
1 and a or sqrt(a) and sqrt(a) or a13/15 and a2/15
1 x 15, 3 x 5
15 and 16. or -16 and -15
The two numbers are -2 and -15
15