What two numbers multiply to -84 and add up to 40

Answer 1

xy = -84

x+ y = 40

y = 40-x

x(40-x) = -84

40x -x^2 = -84

x^2 -40x +-84 = 0

(x-42)(x+2) = 0

x = -2 and 42

-2 times 42 = -84

-2 plus 42 = 40

the numbers are -2 and 42