The difference between two digits is 8. Find the value of the two digits if their product is to be maximum

Answers

Let the number be xy

x - y = 9

Product of x and y = x(x - 8)

P =x² - 8

$\frac{dp}{dx}=2x - 8$

For p max

$\frac{dp}{dx}=0$

i.e. 2x - 8 = 0

x = 4

y = -4

raphael answered the question on January 16, 2017 at 12:23

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