The two numbers that add up to -13 and multiply to 40 are -8 and -5. When you add them together, -8 + (-5) equals -13, and when you multiply them, -8 * -5 equals 40. Thus, the solution is correct.
-10 and -4
-313
77
23
(20 - √229) ≈ 4.867 and (20 + √229) ≈ 35.133
-10 and -4
-313
-113
77
-944
23
55
-27
(20 - √229) ≈ 4.867 and (20 + √229) ≈ 35.133
-40
107
-16