a]
[tex]x^2=3^2+3^2\\\\x^2=9+9\\\\x^2=18\\\\x=\sqrt{18}\\\\\huge\boxed{x=3\sqrt2}[/tex]
b]
[tex]x^2=17^2-15^2\\\\x^2=289-225\\\\x^2=64\\\\x=\sqrt{64}\\\\\huge\boxed{x=8}[/tex]
c]
[tex]x^2=(\sqrt{13})^2-3^2\\\\x^2=13-9\\\\x^2=4\\\\x=\sqrt4\\\\\huge\boxed{x=2}[/tex]
d]
[tex]x^2=12,5^2-7,5^2\\\\x^2=156,25-56,25\\\\x^2=100\\\\x=\sqrt{100}\\\\\huge\boxed{x=10}[/tex]
