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If the sum of two numbers is 32 what will be the largest possible value of their product
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Let x be one of the two numbers.
Then the other number is (32-x), and the product of the two numbers is
=
.
To answer the question, complete the square in the right side quadratic polynomial.
=
=
.
Now, the right side has the maximum equal to
=
at x = 16.
For any other value of x the negative quadratic term in the right side of the expression makes it lesser.
So, the maximum of the product of the numbers x and (32-x) is achieved at x = 16 and it is 256.