Question 890681
 The sum of the squares of two numbers is 197.
x^2 + y^2 = 197
:
The square of their difference is 83.
(x - y)^2 = 83
FOIL
x^2 - 2xy + y^2 = 83
Use elimination with the 1st equation
x^2 + 0 + y^2 = 197
x^2 - 2xy + y^2 = 83
------------------------Subtraction eliminates x^2 and y^2
      2xy = 114
xy = 114/2
xy = 57 is the product