Solution
For this case we can do the following:
[tex]8^2=x^2+y^2[/tex]And we can create the following two questions:
[tex]2^2+z^2=x^2,6^2+z^2=y^2[/tex]If we subtract the last two equations we got:
[tex]6^2-2^2=y^2-x^2[/tex]Solving for y^2 we got:
[tex]y^2=36-4+x^2=32+x^2[/tex]Replacing we got in the first equation:
[tex]8^2=x^2+32+x^2[/tex]And solving for x we got:
[tex]64-32=2x^2[/tex][tex]32=2x^2[/tex][tex]16=x^2[/tex][tex]x=\sqrt[]{16}=4[/tex]