Answer:
You have to use this equation: [tex]a^{2} + b^{2} -c^{2}[/tex]
Step-by-step explanation:
C is the hypotenuse but you need another one so you got to do
[tex]x^{2} +8^{2} =17^{2}[/tex]
now you have to find [tex]x^{2}[/tex] which is
[tex]x^{2} = 17^{2} - 8^{2}[/tex]
[tex]x^{2} = 289 - 64[/tex]
[tex]x^{2} = 225[/tex]
[tex]x = \sqrt{255}[/tex]
[tex]x = 15[/tex]
