Question 840423
let x and y be two number
then x*y = 12
x=12/y
x-y = 4
12/y-y = 4
(12-y^2)/y = 4
12 - y^2 = 4y
y^2 + 4y - 12 = 0
(y+6)(Y-2) =0
y=2 y = -6

When y = 2 then x = 6
When y = - 6 then x = -2