Question

If the sum of two numbers is 15 and their product is 50 what are they

Answer 1

Xy = 50
x + y = 15

x = 15 - y

xy = 50

(5 - y)y = 50

5y - y^2 = 50

y^2 - 5y + 50 = 0

(y - 5)(y - 10) = 0

y - 5 = 0 or y - 10 = 0

y = 5 or y = 10

x + y = 15

For y = 5: 

x + 5 = 15

x = 10

For y = 10

x + 10 = 15

x = 5

Answer: the numbers are 5 and 10.