What adds to get -7 and multiplies to get -8?

Answer 1

-15

Answer 2

Let the number m & n

Hence

m + n = -7

mn = -8

It follows m = -7 -n

Substitute

(-7 -n) n = -8

Multiply out the brackets

-7n - n^2 = -8

Form a Quadratic Eq'n

n^2 + 7n -8 = 0

Factor

( n + 8)(n - 1) = 0

Hence n = -8 & + 1

It will be seen that if n = -8 Then m = 1

Answer 3

-8 and 1