Question 290730
  Remember an identity {{{(a + b)^2 = a^2 + 2ab + b^2}}}.. With this identity, we can solve the problem.
  = {{{(x+y)^2 = x^2+2xy+y^2}}} or {{{x^2+y^2+2xy}}}. whereas {{{(x+y)^2 = 64}}} ok?

  But {{{x^2+y^2 = 36}}};  in the above identity, we dont have the value of 2xy.
So, {{{(x+y)^2 - x^2+y^2=64-36 }}} which is = 28.  Therefore, 2xy = 28.
So, xy = 28/2 = 14.  Answer.  Therefore the value of xy = 14.  I hope this is clear to you.  Best of luck. Feel free to contact me anytime online on any doubts in mathematics.