What two numbers can be multiplied to get 21 and added to get - 17?

It appears that this is a step in factoring

in order to find the two numbers that add to - 17

we need to first find all the factors that multiply to 21

to add to - 17, ll the factors of 21 will be negative

21

-1, - 21

-3, - 7

-7, - 3

-21, - 1

we can try and add the two pairs of each number together

but none of the combinations will work.