What multiplies to 16 but adds to - 8

Answer = - 4 & - 4

The first step of this would be to write all the factor pairs of 16

(1,16) (2,8) (4,4) (-1,-16) (-2,-8) (-4,-4)

Of these, only one pair has a sum of - 8. The (-4,-4) pair. So the answer is - 4&-4