Posted by Scraffii on Sunday, June 10, 2012 at 6:01am.
(x+y)^2 = 168 x^2 + 2xy + y^2 = 168 Replace xy with 4: x^2 + 2*4 + y^2 = 168 x^2 + y^2 = 168 - 8 = 160.