factoring

\((9x-5)^2-(9x-5)-42=(81x^2-90x+25)-(9x-5)-42=81x^2-99x-12=3(27x^2-66x-4)\)

since 27x²-66x-4 is not a perfect square,

\(x=-\frac{\sqrt{133}-11}{9}, \frac{\sqrt{133}-11}{9}\)

this means that, when factorized,

\((9x-5)^2-(9x-5)-42=(x+\frac{\sqrt{133}-11}{9})(x-\frac{\sqrt{133}-11}{9})\)