What two numbers have a product of 3.6 and a sum of 3.8

Answer 1

xy = 3.6
x+y = 3.8

x + 3.6/x = 3.8
x^2 - 3.8x + 3.6 = 0
(x-2)(x-1.8) = 0

Answer 2

x+y = 3.8 ---> y = 3.8-x

xy=3.6

plug first into 2nd
x(3.8-x) = 3.6
3.8x - x^2 - 3.6 = 0
times -10
10x^2 - 38x + 36 = 0
5x^2 - 19x + 18 = 0
(x-2)(5x - 9) = 0
x = 2 or x = 9/5 or 1.8

if x=2 , y = 3.8-2 = 1.8
if x = 1.8, y = 3.8-1.8 = 2
(symmetric answers)

the two numbers are 2 and 1.8

check:
2+1.8 = 3.8 , check!
2(1.8) = 3.6 , check!