Although negative numbers aren't usually considered factors, you can use -21, -3 and -2.
6 + 3 + 2 7 + 3 + 1
I suppose you could use -42 twice. -63 and -21
The factors of 21 that add up to 8 are 1 and 7.
factors of 30 that add to 17 are 2 and 15
How about: 23+3 = 26 as one example
-21 and -1
26
Multiples don't add. Addends add, like 13 + 14 + 15 = 42 but I suspect you want factors, specifically prime factors. 2 x 3 x 7 = 42
They are: 21+6+2 = 29
262
146
6 + 3 + 2 7 + 3 + 1
126 and -63 42 and 21 54 and 9
341
-49 and -7 -42 and -14 -28 and -28
Well it's complicated
There are no two numbers that multiply to 42 and add up to 8. The pairs of factors of 42, such as (1, 42), (2, 21), (3, 14), and (6, 7), do not sum to 8. Therefore, it is not possible to find such numbers.