144k views
20 votes
The sum of two positive integers is 97 and their difference is 37.
What is their product?

1 Answer

0 votes

Answer:

2010

Explanation:

If the numbers are x and y, you have ...

x +y = 97

x -y = 37

Adding these two equations gives ...

2x = 134

x = 67

y = 67 -37 = 30

The product is then ...

xy = (67)(30) = 2010

__

Alternate solution

There is no need to find the actual numbers. We can go directly to their product.

(x+y)² = x² +2xy +y² = 97² = 9409

(x-y)² = x² -2xy +y² = 37² = 1369

Subtracting the second equation from the first gives ...

4xy = 9409 -1369 = 8040

xy = 8040/4 = 2010

Of course the difference of squares can be factored, so we could compute ...

(97² -37²)/4 = (97 +37)(97 -37)/4 = 134(60)/4 = 134(15) = 2010

User Whyser
by
2.9k points