Answer:
4 and 5
Step-by-step explanation:
xy = 20
x + y = 9 ⇒ x = 9 - y
y(9 - y) = 20
9y - y² = 20
y² - 9y + 20 = 0
D = ( - 9)² - 4(1)(20) = 81 - 80 = 1
[tex]y_{1}[/tex] = (9 + 1) ÷ 2 = 5
[tex]y_{2}[/tex] = (9 - 1) ÷ 2 = 4
The numbers are 4 and 5