can someone please help me out with this problem ? i been trying to do this for like 2 days now and i still don’t get it .. also i need some tips on how i can remember this when im doing a different problem

Answer:
Step-by-step explanation:
the Pythagorean theorem is
c is the hypotenuse which is the side opposite of the right angle
plug the numbers into the Pythagorean theorem
[tex]x^2+(\sqrt{26})^2=13^2[/tex]
when squaring a square root, just take the number in the radical and get rid of the radical
[tex]x^2+26=169[/tex]
subtract 26 from both sides
[tex]x^2=[/tex][tex]143[/tex]
find the square root of 143
143 is prime so it can just be written as
[tex]x=\sqrt{143}[/tex]