Question

Let's find x²+y²/2xy
when (x + y) = 9 and (x - y) = 5​

Answer 1

Answer:

4xy=(x+y)^2-(x-y)^2=81-25=56

xy=14

(x^2+y^2)=(x+y)^2-2xy=81-28

=53

(x^2+y^2)/2xy=53/28