What equals 8 when added but -5 when multiplied together?

Answer 1

3

Answer 2

i suppose you mean two unknowns

let them be x and y.

x+y=8....................(1)

xy=-5.....................(2)

from (1), x=8-y

substitute this into (2),

(8-y)y=-5

8y-y^2=-5

by solving quadratic equation, there are two possible values:

y=4+sqrt(21) and y=4-sqrt(21)

therefore, the two numbers are (4+sqrt(21)) and (4-sqrt(21))