[tex]\displaystyle\\\text{The equation is:}\\\\13^2-x^2=15^2-(14-x)^2\\\\13^2-x^2=15^2-(14^2-28x+x^2)\\\\13^2-x^2=15^2-14^2+28x-x^2)\\\\-x^2+x^2-28x=15^2-14^2-13^2\\\\-28x=225-196-169\\ \\-28x=-140~~~\Big|~\cdot(-1)\\\\28x=140\\\\x=\frac{140}{28}\\ \\\boxed{\bf x=5}[/tex]
