First check attached image
By Pythagoras theorem,
[tex]ac^{2} = {bc^{2} + ab^{2} } [/tex]
[tex]→13^{2} = {x^{2} + 12^{2} } [/tex]
[tex]→13^{2} = {x^{2} + 144} [/tex]
[tex]→169 = x^{2} + 144[/tex]
[tex]→169 - 144 = x^{2} [/tex]
[tex]→25 = x^{2} [/tex]
[tex]→ \sqrt{25} = x[/tex]
[tex]→5 = x[/tex]
Therefore, value of x is 5
