Question

The product of two positive numbers is 70. Find the numbers if their sum is a minimum.

Answer 1

you want x+y to be min when x*y=70
so x=70/y
x+y=70/y+y (you need the minimum of this)
you can do this by taking the derivative of it and making it equal to 0
-70/y^2+1=0
y^2=70
y=+-sqrt70
as it is a positive number the answer is sqrt70

Answer 2

both numbers are sqrt 70

Answer 3

35 and 2

Answer 4

35+2=37
for example 10+7=17
so clearly 35 and 2 cannot be the minimum