There aren't any numbers that multiply to 36 and add to -60.
2 * 18 = 36
2 + 18 = 20
-2 * -18 = 36
-2 + -18 = -20
3 * 12 = 36
3 + 12 = 36
-3 * -12 = 36
-3 + -12 = -15
4 * 9 = 36
4 + 9 = 13
-4 * -9 = 36
-4 + -9 = -13
6 * 6 = 36
6 + 6 = 12
-6 * -6 = 36
-6 + -6 = -12
