[tex] \frac{10}{3x} - \frac{x}{3} + \frac{5}{x} = [/tex]
[tex] = \frac{10}{3x} - \frac{ {x}^{2} }{3x} + \frac{15}{3x} = [/tex]
[tex] = \frac{10 - {x}^{2} + 15}{3x} = [/tex]
[tex] = \frac{25 - {x}^{2} }{3x} = [/tex]
[tex] = \frac{(5 - x)(5 + x)}{3x} [/tex]