What is the minimum possible product of two numbers that differ by 8 ?

1 Answer
Nov 6, 2016

The minimum product is 16 and the two numbers are 4 and 4

Explanation:

Let the two numbers be x and x+8.

Then their product is:

f(x)=x(x+8)

f(x)=x2+8x

f(x)=x2+8x+1616

f(x)=(x+4)216

For any Real value of x we will have (x+4)20

Hence f(x) attains its minimum value 16 when (x+4)2=0

That is when x=4

So the minimum product is 16 and the two numbers are 4 and 4